The only way to know is if he tells you. Otherwise, there are no signs. There are only stereotypes, and trying to judge stereotypes will get you into trouble every time.
you really don't unless he confirms it
You can't tell. A gay man might let you know he is gay by acting in a stereotypical way, exaggerating his speech and gestures. But if he doesn't do that, then you can't tell.
There is no way to tell. you have to ask him.
Ask him
There are not really many signs to tell you a man is gay. Some gay men do act feminine which is a clear sign.
You flirt back, but tell her you are gay.
A truly gay man won't settle for a woman for long. Time will tell.
Straight men, by definition, do not lean toward being gay. It's impossible. If a man is gay, then he is gay.
You ask them both what their sexual orientations are. That is the only way to tell.
The only way to tell is to ask him.
No, unless they tickle your todger (man on man)
dude what do you mean?
ask him :)