OK, we are all adults here, so what is a bidet for and how do I use it?

I'm Portuguese and every bathroom has a bidet. Only the really small ones don't. It is something I find in European countries with Latin roots (specially Portugal, Spain, France and Italy).

From personal experience and of others, it is not commonly used, although useful on those few times.

The main uses are to clean:

• Your feet: Sometimes you come home from the beach or had a walk bare feet on your lawn, and you feel like taking a shower is an overkill. Then just use... the bidet. Why is it better than the shower? The bidet is higher, so you can reach your feet to clean them, and normally the faucet is fixed so you can use both your hands without the need for one to hold the water. This might actually be the main use of the bidet, specially on the summer.
• Your bottom: Ever used toilet paper and it seems that it is never going to end? Are you going to a formal event or a date and you want to make sure your bottom is clean after using the toilet? Then why not take a shower? Well, that would take long and it might be unnecessary... Then just use... the bidet! Just sit on it, like you would on the toilet, open the water, and clean it with water and soap like you would on a shower.
• Your genitals: Yes, you guessed it. Before and/or after sex.

When should you do it?

Nobody is going to ask you: Hey, how many times have you used the bidet today?

The bidet fits for those cleanings that would be an overkill for a shower and couldn't be made in a sink, like the ones I've written above.

How should you do it?

I would recommend to use it like the opposite of the toilet in the case of bottom/genitals (like the answer with the picture), because it is easy to reach the area you are going to clean, to control the faucet and to grab a towel (normally, there is a towel bar just above the bidet). Just sit on the bidet, one leg each side and with the genitals close to the faucet, let the water run and use it with soap to clean yourself.

In the case of feet, just wash one at a time. Put your foot on the bidet, let the water run and clean it. After you're done, dry your foot, put it somewhere where it doesn't get dirty again like a bathroom rug or your slippers, and then do the same with the other foot.

Why not just clean waist down in the shower?

Because you wet way more body, making a bigger mess and the need to wet and dry more. And for you might be hard to reach your feet if you really want to clean them.

Edit: Since I've discovered that the "Number two" euphemism isn't global, I'll add here that it means defecation, and comes from the fact that "poo" rhymes with "number two". It's a common euphemism in the UK/America, used as a more polite (or at least, less "visual") alternative to saying poo.

I won't add to the above answers, which have mostly covered the "What is it, how do I use it?" questions, so I'll go straight for the etiquette

Bonus question: What is the social aspect of bidet usage in countries where they are widespread?

Is it implicitly assumed everybody uses this device on a weekly/daily/hourly basis?

It's like any other personal hygiene - the assumption is that you'll use it when necessary. For example, I would likely use some mouthwash after a meal involving garlic bread, or take a shower after the gym... but not everyone would. Regarding the bidet, a lot of people would use it after every number two, with women generally using it more frequently than men for their genital regions. As with much other genital hygiene, it's personal preference and likely related to how soon you expect another person to be in close proximity to those areas of your anatomy... Daily with your number two would be pretty common.

If you've gotten by without using it in your day to day life, though, I highly doubt anybody will notice. It's a bit like moving to a country with dental floss when you've been getting by just fine with toothbrush, toothpaste, and mouthwash. It won't do any harm to add the extra hygiene, but you're not going to suddenly lose all your teeth or start smelling of... well, you get the idea.

Should I dare not talk about it or is there no taboo around it? E.g. when I say "I just used the bidet." does that sound like "I just washed my hands" or is that akin to "I just took a dump", i.e. a rather awkward thing to mention as small talk?

Somewhere in between the two, but probably closer to the latter. You're essentially saying "I just washed my bottom/genitals": before discussing the bidet, think of yourself saying that sentence. If you wouldn't say that sentence in your current context, don't say "I just used the bidet". It wouldn't be automatically considered rude or taboo, but it's a little on the tactless side and perhaps not something you'd bring up at the dinner table. You're unlikely to mention it without a reasonably good reason. How often do you leave a bathroom and tell people you just washed your hands, or used the lavatory?

As living in Southern Europe, bidets are pretty much ubiquitous at any home setting.

Outside homes, they are only normally present in women's toilets, as it is assumed they have got to clean up themselves especially in that time of the month.

I pretty much do not feel confy with them, and use only in those nasty days I go too many times to the toilet; otherwise I just step in the shower and wash at least the relevant bits; faster and less complicated.

As others already mentioned, besides washing the lower parts, the bidet can also double as a feet washer. We take it as very uncivilized to use the basin, or heavens forbid, the kitchen sink to wash your feet as we have already seen french and british doing it while in vacations.

People with kids also have an incentive to keep it extra clean all the time, as toddlers tend to use the bidet to wash hands, as they can reach it more easily than the basin. My daughter used to pick up the soap from the basin and wash the hands there. [and the dolls]

The bidet is also an excellent way of starting to teach young kids how to take care of their own personal higyene with a minimal adult supervision as it is not so dangerous to use alone as the shower.

As far the social aspect, we do not have much taboos around bidets. I have to explain a lot of times to my daughter how to use it, and my wife as a foreign was quite surprised to learn the guys toilets usually do not have bidets. I also can mention that in a rather informal talk without any worries, but needless to say, there is no need to enter into very "technical" details.

As for other doubts expressed in this thread, we have a glycerin soap and two small towels just dedicated to the bidet. There are no mixes with the soap and towels of the basin or the shower.

Finally, bidets can be convenient for the elderly. Often they do have dificulties or even need some help using the shower, and the bidet gives them some degree of independence in their cleaning needs.

There is also another point of using the bidet I had forgotten: water savings/energy savings. While I tend to have a full shower with hot water in the winter time, I can do with washing my private parts and feet with cold or slightly warm water using a bidet, and the water usage/waste is much lower by several orders of magnitude.

Focusing on the subject of using bidets in public places, or hotels, I would only use them only as a last resort. You never know who used them before and how well they were cleaned, and it is not unheard of women getting vaginal infections, as they are more sensitive to that kind of problems. In a hotel I just hop in the shower.

Bidets are in almost every bathroom here (Argentina), excepting public places. Their main usage is for anal (both sexes) and genital (women mostly) cleaning. They can replace or (more commonly) complement the toilet paper. Not everyone uses them, though.

Other answers have covered the usage instructions. I wish to add some socially relevant points about towels:

• Be considerate, you should not leave too visible traces in the bidet towel... you are not supposed to use it to dry your anus, but the surroundings - use toilet paper for the most basic/gross drying

• Be careful. If there is a towel for the bidet, it should be hanging next to it. Use that one -and only that one!- for bidet things.

My understanding, having asked and been given a partial, embarrassed answer, would be that you assume a squatted position over the fixture, without lower body contact, then use the supplied water flow to wash your functional areas after discharging waste in the otherwise appropriate receptacle. Clear yet vague? Typically there is no paper supplied, so the question of wiping and / or drying is not answered. No soap either, required for the setup, right? I've seen bidets that squirt upward, and also, as the one pictured, it squirts outward, across the bowl: either setup seems purposefully aimed for the type of action alluded to above.

I'd like to know if there are more important details left out here -- things we should know. At one time, I stayed in a house with only bidets; they had no toilet paper, nor other paper products that would have worked, and I was informed the rig was better for their septic system (it was a farm outside the city.) No instructions were provided, ahem.

You use it for cleaning your genital and anal areas. This may be BEFORE social (or sexual) meetings or after those areas become in need of cleaning (just a long day since you showered, after sex, exercise, bowel movements or urination, during your menstruation,,, basically when you feel you need it.) I suspect with the widespread adoption of panty pads, that the need for bidets has declined. Usage depends on too many factors, but the bidet is rare in the USA which implies that unlike flush toilets, it is more of a luxury than a necessity. It is possible to over use, it isn't necessary to use soap (culture dependent, I think), and it's possible to be too harsh with delicate areas. The use of anything but disposable (paper) towels creeps me out (except in your own home or your own (guest) bathroom. I didn't know that men used it, and its use for feet was also a surprise.(I'm a typical mid-western American; it's mostly associated with feminine needs here.) As far as how you use it, you shouldn't step into an unfamiliar shower without first turning it on and adjusting the flows of cold and hot water, similarly, you should check out the flows (and temperatures) of the bidet before sitting.

Any almost all North African and Middle Eastern countries Bidet serves simple purpose of washing legs which is a mandatory prerequisite for Muslim prayer

We need a video of well-dressed Indian man showing how to use the bidet.

-- JonathanReez

I'm surprised, nobody has posted this before: In analogy to this answer about squatting toilets, I'll answer the bidet-question with a video by the same well-dressed Indian man:

In spain is pretty common to have a bidet in the bathroom as many others have already answered, the use of it it's up to you, I personally only use it after some liquid dump, those that let you shivering and your bottom on fire... I squat on the bidet, point the faucet to my bottoms and power it up with some cool water in order to clean it up, after soaked it a bit i just rub a little with my hands and then get back to the toilet to wipe it with toilet paper.

I always am fascinated for the curiosity of the people about this, but I not remember no one teaching me how to use it, i guess it's one of those things that you just has to experiment until you are confortable with its use.

Cleaning your feet is another of its uses, you can fill it with hot water and put the feet in the bidet (I have it in front of the toilet and next to the bathtub, so i can six in the border of the tub).

You could use the shower for the both cases mentioned above, but it costs more time and water.

I've never heard of a bidet without toilet paper or a towel to clean up afterwards like Old Uncle Ho commented but I'm no expert on bidets...

A bidet is nice but not every home has space for one and you might find yourself in a bathroom while travelling which doesn't have any such facilities and expect you to use toilet paper like some barbarian. Have no fear, Toto has invented the portable washlet. Here is a completely SFW video on its usage although I must admit I have found its usage absolutely intuitive: fill it with water, hold it between legs with the extended nozzle below your bottom, direct the jet of water where needed and spray. I know I have somehow lived 35 years without using a washlet but now that I have stationary at home and a travel one as well it seems impossible like living without Google or coding without Stackoverflow.