Without her permission YOU DONT
Just firmly squeeze it. Then rub it
Don't or you WILL get slapped ... bad bad baaaddd idea. And really, there is only one way to grab someone's butt :P
not a good idea If you're sure she'd feel comfortable with it grab away. If you're not sure and you're in public you might want to avoid that. Best idea is to whisper in her ear "I wanna grab your butt" and gauge her response. :)
You ask him if it's okay to grab his butt, and if he says yes then you just grab it.The exception being if you're in a relationship with the guy, then you may not have to ask.
grab his butt
Yes
her butt
That she is ticklish.
take your filter off on google and type in girls butt
Just kidding.Most women would find that as a disrespectful gesture but if she permits that kind of behavior then once you two are intimate ANYTHING CAN HAPPEN.
Bribe him or tell him too...if he agrees
Get her consent first.
No, it is inappropriate.