What i would do if it was happening to me is to mock his antics in front of other people. When he does it, call him "gay" and the only reason why he does this is so he can get up close to guys then go home afterwards to jerk off. This will make him insecure and he will worry that people will think he is a homo
You need to make a BIG thing out of it, try and get others to jump on your band waggon and support your "theory"

I reckon if he thinks people believe his is gay and gets his kicks from what he does, he will suddenly stop his nonsense and you can breathe easy...!