What does it mean when a guy pinches a girl's butt?

[BlueBunny]

Well the guy I like he usually hits my butt lightly, but today he pinched it. I know it's part of flirting, but is it the flirt where you like someone or something else? Why do guys even do that? I don't mind, but why?

[Anonymous]

Not a guy but because he wants a peice off ass lol