<human>: Can you condense the text into a few key points?

Ok so my problem is I'm in the military and I wont be in town for much longer but I'd really like to start a relationship with one of the most gorgeous girls I know. 

As a teenage guy my craving for sex is fairly average it's just whenever I think about her it's just kinda primal like I legitimately just want to throw her over my shoulder, take her to bed, and go to town. I fear that if I ask her on a date and I don't talk to her about it the date will only end badly because subconsciously I'll be working under those motives and I'm not sure if that's the right with a girl that I do genuinely like. How is anyone supose to approach the situation? Is sex really that bad to talk about? Physically I think the attraction there and so far all of our conversations have been fairly casual. I also consider myself well worded but I also can't even write something that I feel would explain it in a text so if someone had an idea among those lines that would also be appreciated. I know this isn't the most interesting of topics especially when you take out the aspects of casual sex but any opinions, questions, comments, or statement will help thanks
<bot>: How to ask a girl to be FWB without coming across as an asshole while also leaving the possibility of a relationship open.