When people discuss sex in English, they use certain sexual expressions that anyone familiar with sex understands. The most common and very appropriate sexual expression that should be used when talking about sex is to have sex. When you say you want to make love, you are using a very common sexual expression that is commonly used when two people are in a relationship. Typically, this expression is used by a boyfriend to his girlfriend and vice versa. It is also used by a husband and wife.
Sleeping with someone
Sleeping with someone is another common sexual expression in English. This is a very appropriate term that is used ambiguously. It does not always mean that two people are having sex, but in most instances, it does allude to the fact that the couple is doing much more than simply sleeping with his or her partner. It does signify some kind of sexual activity.
Do it
Do it is another common sexual expression used in English. When children use this term, it means they want something done, but when adults use this term, they usually mean they want to have sex.
Have relations
Have relations is another common English sexual expression. It is not as common as saying you are sleeping with someone and it also does not always refer to having sex. However, in most cases, it does signify that you are having sex.
fornicate
One of the funnier sexual expressions in English, fornicate is used to formally inform someone that you are having sex with someone. Though it does not always allude to having sex, in most cases that is exactly what it means.
Get laid
Get laid is another common sexual expression in English. This is a very common term that is also very ambiguous but it does mean that you want to have sex with someone.
Hook up
Hook up is also something that Americans say when they refer to having sex. However, it does not always refer to having sex.
Hump
Hump is a sexual expression in English that though it sounds childish, refers to the motion of thrusting your hips forward like when you perform sex.
Down to fuck
Fuck is a very common sexual expression in English. Everybody knows what this term means and it can be used in many ways like for example when you say you want to be down to fuck.
Get down and dirty
Similarly, when you say you want to get down and dirty, you are alluding to having sex. Sex up with someone is also a sexual expression used in English in which you express your desire to have sex.
Screw
Screw is another very common sexual expression in English. It literally refers to turning the screw. When you say go screw someone, you mean you should go have sex with someone.
Get a dicking
Get a dicking is a term that usually refers to how a woman performs in bed. Shag is a British term that is quite similar to fuck. It means to masturbate.
These are but a small sampling of the different sexual expressions in English that are commonly used, either sarcastically or in a funny way.