In the beginning of the relationship or even a one night stand, when...

Bring up the topic indirectly will help you not come off as too aggressive or as a horny bastard! :))

One method that always gets me success is asking about dancing---you can ask the girl if she likes dancing, etc. From here you can do many things, but this is what I have done. Girl says, 'oh I don't really like to dance'. I follow up with, "are you kidding me? all girls love to shake their booty, are you telling me you can't get down?" Many times the girls incriminate themselves with an answer and is up to you to keep that going. You can see where the word 'down' can lead to many other assumptions/comments. You'll be amazed how the topic of dancing quickly turns into a sexual conversation and then you just have to make your moves.

Another question that gets me to the topic very fast is asking, 'so you've done anything exciting lately?' Easy, innocent and simple question, but if the mood is already sexually charged, this is a question that will help you seal the deal. If the girl says, 'haven't done anything exciting, how about you', then you need to come up with something that will get to the sexual topic, so I've said, 'well, I don't know if this is the right place to be talking about my exciting life' and well, from there, if the girl is interested in you, she will start asking you questions, and you gotta reel in the fish as they say.

Bottom line is that you need to bring the topic indirectly, and if you can crack jokes about it, the girl will feel very comfortable, and in no time, you will be telling the girl that she is the one being aggressive about sex! :)

You might not have to use words. Just bring her to you and kiss her. If she's really into it, chances are she will then tell you she wants to go somewhere with you.

You shouldn't even have sex at all till you get married. Sex remains a sin for now, people who do it end up in hell forever.