How do I know if he is gay?

Okay, I have this friend (i'm a boy by the way). He's a boy and he always makes these jokes about him being gay or being a pedophile. I almost believed him. Once in a while he pretends that he's "attracted" to me like hugging me really hard from behind or rubbing his d**** behind my butt. One time he grabbed me from behind and whispered "Get on you're knees." And I struggled to be free. He let go eventually and he just laughed. I don't know if he's gay or bisexual or what his sexuality is. Help! (I'm gay too by the way. But he doesn't know.)