Teenage Tent Trauma?

I was recently on a Duke Of Edinburgh expedition. There was a boy in my group who I regulary talked to at school and he would flirt with me most of the time. On the walk he was flirting non stop and later that night he crept into my tent late at night and we had a '' session and then we fell asleep in the same sleeping bag. The teacher heard us laughing and he came over to our tent and was really angry that I had a boy in my tent. The boy got kicked out and we all went to sleep. The next morning he wasn't exactly 'chatty' and he got split into another group. When were on the bus home he seemed to ignore me but when arrived back at school and we were clening the bus out, he was flirting with me again. I havn't seen him for a week as we have been on work experinece. I really fancy him so how should I approach him / what should I do ? Please Help . Thanks Sooo Much :)