when he's thinking of having sex with another male
Lady Gaga has stated that she is bi in many interviews, so that's how we know that she is bi.
He will have to tell you unless you catch him in the act, but he could still be bi unless he says he's gay.
There is no magic answer. The only way to know is to talk to him about it. Any time you open up your heart, there is risk involved. Sometimes the risk is worth it.
If he f*cks guys.
Person attracted to man and woman
i think it is a china man name Bi-shXo
Obviously, if he likes guys. Also; if he doesn't feel any attraction for women, but would rather be with a man, there you have it. But if you like both; you might just have mixed feelings. Or you could be bi.
If I had to guess, I'd say bi. Don't know for sure.
Just tell her you care about her as a friend, Tell her you know she is Bi... let her know that you are proud to be her friend and that nothing will change that. Be kind to her.
The only sure way to know if anyone is gay would be for them to tell you, or for you to catch them in the act. If he's bi he can have a girlfriend or a boyfriend (he wouldn't "need both") and there would be no problem.
ask him :)
Ask her.