Is my best friend bicurious?

I know he definitely likes women--he's kind of man-ho. He's gotten me to film him with girls many times. I've never known him to do anything gay with anyone. But one time we were working on Chaturbate, and he came right when I did--as if he was turned on by it. I also thought I caught him looking at me. I don't know. He insists he's straight. What do you think?