Can someone help me with this girl?

Sup people? I've asked on this yahoo answer thing about this same girl last time (i just don't wanna regret like last time i had this chance) Anyways.... There's a girl at the same high school as me. (i'm a senior) and we haven't been talking for a while. {loads of project crud and essays ... gotta hate those essays} well... i got some advice from this and talked to her. haha... whenever we see each other .... i sorta tease her (the good way) and she get's all "i hate you! XP" whenever she's behind me or somthing.... she puts her arms on my shoulders and sorta leans on me and tries to tease me the same way i do to her. she always covers her face (in a shy way whenever her friends tease her about liking me) can anyone tell me what the body language is saying? how should i act whenever she wraps her arms around me? (i tried doing the same.... but it's hard XD..... she's always behind me) thanks in advance dudes