Hell, It's about time!
This isn't a question on the anatomy of sex... I'm not dense. The question is how does one know when someone wants sex from you, and how do you know when to pursue it. An example is say you meet someone for the first time. You start getting to know one another thru out the evening, you get that feeling that I can probably have sex with this girl/guy, and suddenly your in the sack screwin... but how do you get to that point? How do you know that this person did in fact want to have sex with you as opposed to someone else who didn't. Is it body language, hormones or is it deeper then all that.