Lust at a young age, complex confusion.?

Ok, so Im 17 still a virgin, I like male & female. Also I just graduated high school. I'm curious on how to ask my ex if she'd wanna mess around? Recently well like 2 months ago we broke up because I was leaving high school & she's a year younger so she was staying. But I was still going to be close by because Im going to a community college but we always had these phases were we wouldn't even talk to each other, until I spoke up.Anyways she cheated on me twice, but not like intense just popped kissed other girls. One of them because she was drunk and the other one I don't know. We kinda were together for a long time since 11/12/08 but we broke up 3 times and took breaks like 2 months or less then got together. The first time I got together with her, I said to myself I'm going to wait until the guy of my dreams comes & then dump her. But likewise that never happened and eventually I fell in love for the first and so did she but I wasn't her first. There had always been drama since the beginning, to now the ending. When we broke up we'd stayed 2 hours together, me asking her why can't you answer my question? Which was why does she treat me bad? Like everyone could tell..and I like practically gave her the world. Before we broke up we were getting more intimate then before. I was liking that because I felt so comfortable, and you know us human beings :D ha. Anyways! she leaves hints here & there, & so do I. What I wanna know is, should I ask her? Can we mess around for the last time? I don't wanna go all the way, even though that lust. but there is something that wants me to just play with her...should I do it or not? Dont' tell me oh no it's bad because this & that she played you. Tell me as if YOU were in the situation.And if its a yes, then how should I ask her?if it's a no, how do I get rid of this feeling?