Frankfurt Sex Guide advises where to find sex, working girls, prostitution, street hookers, brothels, red-light districts, sex shops, prostitutes, erotic massage parlors, strip clubs, FKK Clubs and escorts in Frankfurt, Germany.
Frankfurt (German: Frankfurt am Main) is the business and financial centre of Germany and the largest city in the German state of Hessen. The city is known for its futuristic skyline and the busiest German airport.
- 1 Sex and Prostitution in Frankfurt
- 2 Frankfurt Female Escorts
- 3 Red Light Districts
- 4 Prostitutes and Sex Workers
- 5 Street Hookers
- 6 Live Sex Cams
- 7 Adult Locations
- 8 Escort Services and Agencies
- 9 Erotic Massage Parlors
- 10 Brothels and Sex Clubs
- 11 Strip Clubs and Striptease
- 12 Karaoke and KTVs
- 13 Swinger Clubs and BDSM
- 14 Sex Shops and Adult Stores
- 15 Love Hotels and Short Time Hotels
- 16 Nightclubs and Bars
- 17 Gay and Lesbian
- 18 Other Adult Services
- 19 Dating
- 20 Transsexuals and Shemales
- 21 Sexual Services for Women
- 22 Male Escorts
- 23 Sleeping and Girl Friendly Hotels
- 24 Stay Safe
Sex and Prostitution in Frankfurt
Adult entertainment is huge business in Frankfurt, unsurprising given the mix of large numbers of lonely business travellers and legal prostitution.
See also: Frankfurt Escorts
Frankfurt Female Escorts
If you prefer to date a lady in your hotel, you can call some private escort girls in Frankfurt. Some of them are part time providers, but most of them are pros. It is not easy to find the good ones, because a lot of the profiles you find will be fakes.
If you are looking for a serious escort agency, you should check escort forums for reviews of the agency and the girls listed there. Usually ladies at higher priced agencies in Frankfurt are part time escorts and business ladies or students in their normal life. At the high class agencies the agency owners put importance to certain criteria such as an elegant and beautiful look and a good education and background. The ladies will be casted in a personal interview and the agency owner only selects the lady which guarantee to match the good image of the agency.
Red Light Districts
The Red-light district area in Frankfurt is known as Bahnhofsviertel, the block directly opposite main railway station (Hauptbahnhof). It is one of the largest Red-light districts in the whole world, and literally this place is huge and full of sexy whores. Here you will find a number of Eros Centres, strip clubs, sex shops and chat-up bars (where girls will talk to you while sipping the €50 glass of drink that you’re paying). Beware of unscrupulous people hanging around this area, and be careful when entering an Eros Centre or strip bar. Always make sure you know the cost of anything you buy before doing so, and employ as much common sense as you have left. Obey those rules and you should be fine: Frankfurt’s red light area is as safe, professional and organized as the sex industry gets.
Most brothel buildings in the Frankfurt redlight area have 4 or 5 floors and each floor is filled with prostitutes. Some of the brothels have only under 5 whores per floor, but some have many more. Because most bordellos have so many floors, unless you are athletic your legs will get tired before you have toured all the whore houses in the area.
You can read more about Frankfurt Red Light District from here: Bahnhofsviertel
- See Also: Window prostitution
Prostitutes and Sex Workers
To have sex with prostitute in Frankfurt is rather cheap. The standard routine in red light district is a short blow job followed by intercourse until you cum. This will usually last 10-20 minutes. Prices vary from 20 to 50€. The hookers make their own prices. Some are desperate for the money and will offer themselves for 20€. The good looking hookers will always charge at least 30€. If you opt to stay for 30 minutes to get unrushed service the price will range at about 50€. 1 hour will cost between 60 and 120 € depending on your negotiating skills, the girls attitude and on how busy the house is at the particular date and time. On a slow Monday evening you will get away cheaper than on a hot Friday´ night. It is recommended to negotiate the price before you make a deal if you pay for the time or a one time cum.
Normally the prices include oral sex (with or without condom depending on the prostitute) and sex (with condom). Some ladies offer anal, massage, etc for a small surcharge.
Repeat customers usually get better service than tourists. It is advisable to pretend that you are in city for a longer period of time. This way you get better service because she wants to see you again to get more money.
Be aware of the fact, that there are some scammers that want to squeeze out as much cash out of you as possible and returning as little as necessary or nothing at all.
When you negotiate the price make sure:
- What is the maximum time?
- How many times you will be able to cum?
- Are you allowed to change positions during intercourse or does extra positions cost more?
You will avoid to get scammed if you make things clear from the beginning. Some hookers (usually the German whores that believe they are something better than their Latina and eastern European counterparts) promise you everything. Don't lose your head! If you do, this may happen: Suddenly she will only allow you to lower your jeans a little and will start to give you a hand job. She will ask for more money for oral sex, than she will charge another 20€ if she takes off her bra and each other promise will set you back more and more financially without any real benefit. This scam is designed to get you to a point when you will just say, NO and leave with less euros and no satisfaction at all. Rather give up your initial investment of 30 € and venture for a new girl if you get caught in this trap. The girl has secret alarm buttons in her room and within a short time 2 or 3 flatheads with pitbulls will be waiting in front of her room and not let you leave before you pay her. They will ask for money themselves. Usually pay is before service. However it is advisable to pay after if possible or deposit the money on a table visible for the lady so she can take it after the job is done.
Regular street prostitution (Straßenprostitution) in Germany is often very well organized and sometimes controlled by pimps. Most German cities however established "Sperrbezirke" (off-limits zones) and charge the street prostitutes an amusement tax, that in the city of Bonn for instance is paid by the streethookers at parking meters, 6€ for a period of about 8 hours at nightime. The same fee is collected from sex workers in apartments and brothels, sometimes by municipal tax collectors in person. Some street whores have a nearby caravan, others use the customer's car, still others use hotel rooms. With recent economic problems, in some bigger cities "wild" street prostitution has started to appear: areas where prostitutes work temporarily out of short-term financial need. A "Sex drive-in", or "Verrichtungsbox", is a facility of structures to enclose cars to provide a safer place for sex workers using cars.
Where to find Street Prostitutes
Street prostitution is legal in Frankfurt in one part of the town, called the tolerance zone. This is in the two parallel side streets of Theodor-Heuss-Allee (between Galvanistrasse and Kreuznacher Strasse), directly north side of the Frankfurt fair. The side street leading out of the town also has a few transsexuals. Rates are starting at 25 Euro for full play, but can also be lower depending on the urge of the lady. There is a much lower chance to find prostitutes, if it is daytime, not exhibition or very cold outside.
Hygienic standard is not very high there and a lot of girls there also come from the drug scene, so you will have a high risk to get trouble with the whore or with her pimp.
There are also street hookers available in the Bahnhofsviertel, but there street working is prohibited and you will get fined if caught by police.
Some of the sex shops offer peep shows and here are a few girls waiting outside the shops that will be willing to come into your peep show or video cabin with you and give you a hand-job, oral sex or even full intercourse.
Live Sex Cams
Can I watch Live Sex Cams in Frankfurt? - Yes, you can! Basically you can watch our online live sex shows for free anywhere in the world if you’re connected to internet. Join to get 10 free private teasers and 9.99 credits for free! You can choose any girl from our trusted Live Sex Cams!
Live Sex Cams are booming at the moment. Webcam models can be found from all over the world and you can find girls, guys, trannies, couples and groups of different ages performing to you. Watching live sex shows is usually free, but if you buy some credits, you will have much better chances to see adult action as desired! It's possible also to hire a webcam model to a private chat room where you can ask the person to fulfill your fantasies.
There are many adult locations in Frankfurt. But the most well known sex hot spot is the red-light district which is located right next to the main railway station. There are many laufhaus walk-in brothels in the area and you have an thousands of girls to choose from. More whore houses and sex clubs can be found around the city from different areas.
Escort Services and Agencies
There are many different type of escort agencies in Frankfurt. Prices range from 150 to 300€ per hour. Frankfurt is a big city, so you can find very different kind of girls from all over the world working in Dusseldorf as escorts.
Erotic Massage Parlors
- Zeil 22, 60313 Frankfurt am Main
- Albanusstrasse 37 65929 Frankfurt am Main
Frankfurt has a good variety of erotic massage salons. Best ones offer four-hand massage and all kind of extras you can imagine. Prices for one hour erotic massage and a hand-job is usually around 70-150€. Some of the massage salons only offer basic Happy Ending, but others will offer sex, blow-job, rimming massage, dominant massage, golden showers and other kinky things. In Frankfurt, Thai and Asian operated body rub salons tends to be cheaper, but also not as luxurious and clean as others massage parlors
Massage and Body Rubs
Brothels and Sex Clubs
Germany has always had brothels and red light districts. About 30 years ago in a town called Lichtenberg outside of Bonn a man started the first FKK club. The term FKK means "Frei Korper Kultur" Free Body Culture which translates best to "nudist". The difference between a normal brothel and an FKK club was the presentation and system. The owner and inventor named "Bernd" got tired of the brothel system where price was negotiated, dark lighting, pressure sales and the workers bodies were hidden by clothing. Starting out in his basement he opened the first FKK club with his own system. Women were totally nude, the club had normal lighting, prices and services were set Above all service was based on quality and customer satisfaction. Bernd's main customer base were local business men. The club is located in a small village in his basement. He charged an entry fee which included all you could drink beer, alcohol and snacks. Women were paid a flat fee for a session which averages about 30 minutes. The concept caught on and soon the club took over the entire home.
As the years went by numerous other clubs opened and used similar terms such as Sauna Club or FKK Club. The main difference is all the clubs offered a sauna but FKK clubs meant the women were totally nude.
Years ago the clubs were not tourist friendly and one had to speak some German to enter. Today some clubs still limit visitors and forbid entry to some guests. Tour providers have opened many doors to tourists and convinced clubs that foreign visitors were another form of income. Guests are picked up from major airports, transported to the clubs and then to a hotel in the evening. Tours were provided in the English language as well as Japanese. Tour packages came in 6 or 8 day tours and visited 10-12 clubs during the duration. A guide is provided to the guests who explains rules, culture and history of the clubs in their own.
In spa town of Aachen, men may go window-shopping for sex; they can have unlimited sex with as many girls they liked for 99€ at a “flat-rate” brothel in Berlin; or they can visit Pascha, an eight-story “mega-bordello” in Cologne.
Prostitutes in Germany all work freelance - instead of being paid a salary, they rent rooms from Brothel owners who sometimes still do not question their health or see proof of insurance. The city of Stuttgart is home to high-class brothel Paradise, where girls were required to be completely naked at all times while men walked around in bath robes.
FKK Saunaclubs are very popular in Germany (and also in Austria and Switzerland). The guests pay entry fee (50-150€) and got several services for their money. The most commons services are: solarium, sauna cabin, bar, infrared cabin, showers. The most of Saunaclubs offer erotic or sexual services as well, from porn movies to private sex with girls.
Brothels, Sauna and FKK Clubs
There are several Brothels in Frankfurt, where you have a selection of 3 to 10 prostitutes. Most of them you will find in normal apartments all over Frankfurt. There you can have fun for 80-150 € for one hour.
If you prefer a higher class entertainment with sexy hookers, you should not miss to visit one of the famous Frankfurt FFK Sauna Clubs. Most of them will offer a very good spa area, high motivated girls and all for a reasonable price. FKK Clubs are the most famous brothels in Germany.
Strip Clubs and Striptease
- Moselstraße 46-48 D-60329 Frankfurt am Main
In the red light district you will also find a lot of strip clubs and bars. In this bars you can watch girls doing table or pole dance, you also can invite the strippers to come to your table and drink with you and in the most clubs you can also get a private dance or even a full service session in a private room.
How it will work in a Strip Club?
When you enter the Strip club, you first will have to pay a entry fee of around 10 to 20 Euros. Than you will take place and enjoy the strip show of different girls (and sometimes somewhere also guys or transexuals).
A strip club is not a place where you should go alone, so you will find a lot of groups there, for example bachelor parties. Some clubs also offer a limo pickup service for a reasonable price (for example the Platinum), if you plan to party there.
If you like one of the girls, you can ask a waiter to call her to your place. She will come and sit down beside of you just for chat. But for that they will expect you to order some champagne or drinks for her. If you like her, you can ask her for a private dance. For that you will have to pay between 20-40€. In most of the clubs you also can have a session in a private room for around 150-250€ and get full service. Most of the clubs will not allow you to take out the strippers and the girls also will get big trouble, if they meet a customer outside the club.
If the club stuff on the street try to "push" you in the club, better be aware of this place. As more pressure, as more risk they will only try to scam you with overpriced drinks.
The strippers will get a commission of the drinks you order, so if you don`t be careful, could be you will have to spend a unbelievable high amount only for overpriced drinks ordered by the girls! So better check the menu twice! Could be they will order several bottles of champagne for sometimes more than 200€ and the bill will rise up very fast!
Karaoke and KTVs
Swinger Clubs and BDSM
ALT.com is the best place for local singles, swingers, and couples in the BDSM community to connect with those interested in submissive sex, power exchange, locating persons for new slave roles, erotic BDSM, bondage & fetish sex, as well as live sex dates. Find thousands of play partners for whatever your fetish may be; bondage, foot, cockold, spankings, role-play, electric or water play, sadism and masochism. So whether you have the desire to explore your unrealized fetish fantasies, or you are extremely experienced and would love to train someone new, ALT.com is a community designed for people with like-minded interests to find and connect with each other.
Partytreffs and Pauschalclubs are a variation on partner-swapping swing clubs with (sometimes, but not always) paid prostitutes in attendance, as well as 'amateur' girls and couples. Single men pay a flat-rate entrance charge of about 50 to 150 euros, which includes food, drink and unlimited sex sessions, with the added twist that these are performed in the open in full view of all the guests. Ladies normally pay a lower entrance fee than men or no entrance fee at all.
In Frankfurt, there are also swingers clubs where prostitution is not allowed. To get in to these type of premises you often has to be a single woman or a couple. Single men are usually not allowed, or they have to pay a higher entrance fee if allowed. Sometimes single women are allowed free entrance.
Sex Shops and Adult Stores
If you don’t feel like visiting or cannot find any local sex shops in Frankfurt, you can easily order adult products from Online Sex Shop.
Most of the sex shops in Frankfurt are connected to the porn movie theaters. Here you can get also "real" fun with yourself while others will watch. Sex shops have also huge variety of movies, toys and condoms.
Some of the sex shops offer peep shows and here are a few girls waiting outside the shops that will be willing to come into your peep show or video cabin with you and give you a handjob, oral sex or even full intercourse.
Love Hotels and Short Time Hotels
Love hotels are popular in some parts of Asia, especially in Japan. There are also many love motels and short-time hotels in South America. Unfortunately you cannot find any real love hotels in Frankfurt.
Nightclubs and Bars
There are many nice nightclubs and bars in Frankfurt where you can try your luck to find sex for free. Lots of locals and lots of tourists and business people.
Gay and Lesbian
Gay modeling in internet is getting more popular all the time and it's a big market alongside with gay porn. You can watch gay live sex also in Frankfurt as long as you are connected to internet. Check it out: Gay Live Sex Video Chat
For gay visitors, the city offers even more convenience, with its condensed area of LGBT bars and clubs, the so-called "Bermuda Triangle" (bordered by Konstablerwache, Bleichstrasse and Eschenheimer Turm) located right at the heart of city. Every shade of gay, bi and lesbian is well represented here in this compact cluster, from mainstream homo to indie queer. Frankfurt's Pride (or CSD, as it's called here, short for Christopher Street Day) happens every July, with a plucky Saturday parade and a huge street fair lasting the whole weekend.
There are many great gay cruising clubs, gay bars, gay saunas and bathhouses.
Gay Beaches and Water Parks
- Langener Waldsee (Langen Lake). Take the S3 or S4 train for Darmstadt to Dreieich-Buchschlag stop. The path to the gay beach branches to the left of the one leading to "Badesee."
- Rebstockbad (Zum Rebstockbad 7), general public water-park, gay-popular on Thursdays, especially in the sauna section.
Gay Cruising Areas
- Old Opera, Opernplatz, 60313 Frankfurt am Main
- Close to Metro.
- Bethmannpark, Bäckerweg, 60316 Frankfurt am Main
- In the bushes near Friedberger Anlage.
- Friedberger Anlage, 60313 Frankfurt am Main
- Cruising Spot in downtown Frankfurt! In fine weather after dusk. On weekends until the early morning hours.
- Toilet Metro Station Bockenheimer, Berliner Straße , 60311 Frankfurt am Main
- During the day, many students. Closed from approximately 18:30 clock.
- Toilet subway station Messe, Frankfurt am Main
- In the B-level underground U4 - Output fair tower.
- Konstabler Wache, Konstablerwache, 60313 Frankfurt am Main
- On the B-level in the toilets.
- Main River,Frankfurt am Main
- North side from the Iron Bridge turn left towards the eastern harbor. Evening in summer weather many single gay men go on the field and on the park benches. The same picture on the left side but towards the western harbour.
- Parking A661 between Offenbacher Kreuz and exit Taunusring, Frankfurt am Main
- Parking between Offenbacher Kreuz and exit Taunusring.
- Parking A3 immediately after the Frankfurter Kreuz, Frankfurt am Main
- Würzburg: Parking directly by the Frankfurter Kreuz.
- Rebstockbad, Zum Rebstockbad 7, 60486 Frankfurt am Main
- Gay Cruising in the showers and cabins, especially Wednesday to Friday.
- Schultheis Weier, Frankfurt am Main
- The Schultheis pond located in a nature reserve between the Offenbacher districts Biirgel and Rumpenheim and just on the other side at Frankfurt Main -Fechenheim! Textile beach with beautiful sand beach, naturists find beautiful lawns and shady trees. Actually, ideally, no entry, skinny dipping allowed, showers and toilets (big + lockable) and abundance of forest around it exists. And so to get for: Best by bike or public transport: Tram 11 to Fechenheim mail, over the Main web, then left, next dirt road to the right and straight on. Or from the direction Offenbach City by bus 101/107 to Böckler- settlement, then turn left and go through grade.
Gay Cinemas, Kinos and Adult Arcades
Check out the Sex Shops & Adult Stores section from below!
Other Adult Services
The basic form of BDSM (Bondage & Discipline/ Dominance & Submission/ Sado-Masochism) is all about the erotic and sexual acts and mind-sets of dominating and relinquishing control.
In the past few years BDSM has got a pretty bad reputation, but the basic principles can be extremely liberating and in the long run if you engage with it, turn you on in a way that you would never even have thought about. The fact that the standard media representation of BDSM is of something seedy and weird and sometimes make it feel like a taboo.
But if girl take the reins it can actually increase their sexual confidence and sense of agency, while giving men a break from having to be 'on top', psychologically as well as literally which is the standard dynamic for most lovers. The trick is to have an open mind to sexuality, obviously anything which causes harm to your loved one or yourself is not good, but we're all humans and exploring the parts that make us a little different is what can make a hugely beneficial relationship.
Dating in Frankfurt can be a bit tricky due to cultural differences, so your best bet is to sign up for a dating site before your trip so you can meet a few locals ahead of time. AdultFriendFinder.com lets you meet local members in Frankfurt and get to know them on a personal basis before you arrive. Take advantage of site features like live chat and member to member webcams so you can begin flirting before arranging a face-to-face meeting. Since your time in Frankfurt may be limited, get to know each other’s desires beforehand, so that when you meet you can start having some real fun.
Transsexuals and Shemales
Finding someone for transsexual dating when you’re on the road can be a bit tricky, so your best bet is to sign up for a dating site before you go so you can find locals ahead of time. TSdates.com is a dating site designed to help you find exactly what you are looking for in your hookup in Frankfurt. Take advantage of site features like live chat and member to member webcams so you can begin flirting before arranging a face-to-face meeting. With over 40 million members, and thousands of transsexual members around the world, TSdates.com is the world’s largest site of sex-minded friends for discreet encounters and will help you find your next transsexual play partner.
Where can I find shemales in Frankfurt? You can watch transsexual live sex shows in Frankfurt as long as you are connected to internet. Check Now: Tranny Live Sex Video Chat
There are some ladyboy prostitutes working in Frankfurt but most of them are not German.
Sexual Services for Women
A comparatively small number of male prostitutes in Germany offer sexual services to females, usually in the form of escort services, meeting in hotels. Usual cost for evening with a male escort is 100-600€. Some of the male escorts also offer weekly rates such as 2000-6000€. Most male escorts in Germany come from Southern European countries, but there are some real Germans too.
In Germany, somewhere there are around 20 escort agencies cater to women. You can see the pictures of the men online: age, height, physique. Some of the men also list preferences: oral, anal, group sex. Some men set limits and some do not.
Most female customers are from early 30s through mid-50s, and are normal women. Most female customers like the feeling of being loved and not just sex like most male johns.
Sleeping and Girl Friendly Hotels
Frankfurt has plenty of accommodation but during major trade fairs, prices at even the cheapest hotels will suddenly skyrocket with charges of over €300/night quite common. Plan well ahead and alternatively, consider staying in nearby cities like Darmstadt, Neu-Isenburg, Bad Homburg, Mainz or Wiesbaden which are under an hour away by S-Bahn. If none of these works then Mannheim might be a last resort as it is 30mins by ICE high-speed train (but train ticket is rather expensive).
Frankfurt is the banking capital of Germany so most people are business travellers with an expense account. If you intend to stay for longer periods, ask for discounts or corporate rates. If you need to depart early or arrive very late then hotels around main station are a valid alternative to expensive airports hotels as it is just a 10 minutes ride from Terminal 1 by local train.
Many of the hotels in Frankfurt are located around the Hauptbahnhof, but this is also the red light district in Frankfurt and is also known for the many beggars and druggies who hang around. Although the area is well policed and quite safe, many tourists are often left with a somewhat negative impression of Frankfurt after staying in this area. If it’s not for you then there are plenty of cleaner areas in the city which you may find more suitable.
Before booking your hotel in Frankfurt, make sure that it's OK to bring your "local girlfriend" to visit your room.
See also: Global list of girl friendly hotels
Frankfurt has the highest per capita crime rate of all communities in Germany for years.
So, for German circumstances the city is quite dangerous, but violent crime is not as common as in some cities of the United States of America, among others because of a stricter weapon law in Germany.
The high crime rates of Frankfurt can partly be explained with some statistical reasons: smuggling and similar offenses at the airport as well as anything concerning credit card fraud anywhere in Germany is registered in Frankfurt, since the main credit card clearing company is based in Frankfurt.
Physical crime is in general concentrated in the red-light district around the central train station, which also is the hangout of many drug dealers/junkies. The Gallus area west of the central station doesn't have the best reputation, either. Nevertheless, Frankfurt is still safe and it is highly unlikely that you will face armed robbery or other violent crimes. Use your common sense and avoid drunken or aggressive people at night.
If you have a problem or are being harassed, ask the police for help. The German police and the Frankfurt Ordnungsamt (City Enforcement Officers) are clean, competent and generally helpful. Germany is very bureaucratic but structured; as long as you behave respectfully toward the police, you should have no problem.
On the other hand, buying and smuggling drugs are major offenses with dire consequences.
Lately, bogus police officers have been an issue. All real officers have a green card with photograph and number, and no officer will check cash. Ring 110 if you get any trouble.
Drugs and beggars
The central station area (Hauptbahnhof) is known for being a center for homeless and perhaps drug users. It has improved much in recent years, but you will still occasionally be bothered by beggars. The drug addicts generally don't bother people, and the beggars will ask for Kleingeld (small change), which by their definition is anything between €0.20-2. One way to fend off beggars is just to say you do not speak German (and this might just be true for you anyway!). They will often switch to English then, so just pretend you can not speak that either (just shake your head, or say "No English") and they will get frustrated and leave you alone. If you think you are up to it, you may find it useful to know one or two sentences in the Frankfurter dialect to mimic locals, as tourists are often regarded as more profitable targets for beggars. Some of these phrases would be hoer uff (stop it), lass misch in ruh (leave me alone) or mach disch ab! (go away!). A polite Nein, danke (no thanks) will usually not do.
- Bremen, Hamburg & Bielefeld
- Cologne, Düsseldorf, Dortmund, Essen, Bonn, Duisburg & Bochum
- Berlin, Dresden &Leipzig
- Munich & Stuttgart
- Germany, Netherlands, Czech Republic & Austria
- Amsterdam, Vienna & Prague
- Age of consent in Germany
- Prostitution, Street prostitution, Global prostitution prices
- Sex topics & Phrasebooks, Sex worker, Prostitute types
- Red-light district, List of red-light districts all over the world
- Brothel, Escort agency, Call girl, Erotic massage, Strip club
- Sex tourism, Sex industry, Countries with most prostitutes
- Sex vocabulary & Abbreviations, Humorous sexual terms
- Gay, Lesbian, Gay and lesbian travel, Bisexuality, Ladyboy
- Age of consent, Stay safe, Scams, Safe sex, STD, HIV/AIDS