Penetration = sex, as does busting a nut in front of someone else. Dick to mouth, finger to pussy, whatever. And if I'm watching a girl go to town on herself, we're both naked and I'm whacking it we're having sex.
To the knuckleheads that say only intercourse is sex - Would you suck a guy's dick? I mean it's not like you're having sex or anything so you can't be called gay. It's just like hugging or shaking hands, right?