This is a kind of sex that involves one person using their mouth or tongue on someone else’s genitals.
It’s sometimes called “giving head” or “going down” – presumably because it’s (sort of) your head that is giving the pleasure and, if you are face-to-face, then that’s the direction you move to do it.
As with all aspects of sex, different people like different things – it could be licking, kissing, sucking, nibbling or something else entirely. Communicating and finding out what the other person likes is the best advice we can give on this – what one person loves another might really dislike.
Oral sex performed on a penis is also known as fellatio, and is frequently called a “blow job”. This is confusing because, in most cases, you aren’t going to be trying to blow it up like a balloon – no blowing is usually involved. (Although, as per the above – if that’s what feels good to the recipient then by all means go for it!). In fact, the “blow” part is thought to date back to the 1600s when “blow” meant to bring someone to orgasm, which makes a bit more sense.
It’s also worth mentioning ejaculation here, especially in relation to fellatio. You should be aware that if your partner reaches orgasm, they are likely to ejaculate and that can mean a sudden, quite forceful spurt of liquid. Some people like this to happen in their mouth and others don’t – what you like is up to you – just be prepared, so you don’t end up choking! If you’d rather not get a mouthful of semen, then when your partner is approaching orgasm, you can switch to using your hand or another form of stimulation to avoid this.
And, if you are receiving oral sex and are about to ejaculate then it’s only good manners to try and make sure your partner knows what is happening – whether it’s by saying something (e.g. “I’m getting close”, “I’m going to come”) or by making a few sounds, so they know things are reaching a climax.
Oral sex on a vagina can also be called cunnilingus. Presumably, if (as above) “blow” just means to give someone an orgasm, then it could be called a “blow job” too, but we’ve never heard it used like that. There’s other terms used for cunnilingus as well – “eating out”, “licking out”, “dining at the Y”, “tipping the velvet” and many others. No doubt there are loads we haven’t heard of too.
We might be sounding like a broken record here, but the most important thing is communication – as long as you both know what you mean, it doesn’t matter what words you use. And, if you’re not sure what someone wants, then the best thing is to ask them.