My best guy friend is hitting on me?

So like im with this great guy. We rnt dating but we r "together" u kno. I also have a close guy friend. Hes really fun to be around and stuff but it seems like hes starting to like me. He always hugs me and puts his arm around me and stuff. The other guy im with seems to be annoyed by it. My bf knows that i dont like my guy friend, but hes a really good friend so i hug him back and stuff. i dont want my bf to start thinking im flirting back, what do i do?