yeah like briekittie said. they know we like it! my guy does it to me all the time.
umm because guys know we love it. duhh
because is an arousal mechanism.now, I do that on girls that I'm dating and if they let me do that then I know I can go one step further; on gfs I do it cause I know they enjoy it.
I guess it's just after a certain point in a relationship we pretty much feel the stop sign is down & we can touch here or there. WHY? We like bottoms almost as much as we like chests too.