Does he like me or my bum?

I really like this boy hes 17 and im 15..but does he like me...so he slided his bum against mine one time when walking past even though there was loads of room to get past...he seems to look at me alot...my friend sed that he looked at my bum when i turned around and his eyes always seem to look really bigg..but he never seems to make conversation and when i randomly appear sometimes and then he notices he like freaks out and turns around so he cant see me...btw we have never spoke...and we live apart but i will see him next in june at a party...i have made it soo obvious for him that i like him...so does he like me or my bum and if you think he likes my bum how can i make him like me also why hasnt he bothered making convo if he knows im interested...im the really shy one and i dont think hes that shy...