only had about 6-7 girls over the years that had this special technique done to me. that's when she takes your dick on her ass crack and then w/her butt cheeks clamps and squeezes your dick. one of those girls (i'll call her nancy) had real ass muscle control so she could squeeze really hard. not hard like the japanese lady who broke a metal spoon while applying that technique on some hbo documentary, but hard enough that it felt like she could squeeze and pull your dick right out and yet feel real awesome at the same time. this technique is best when the girl has a lot of ass cleavage.
i remember with nancy once condom slipped right off and i picked it up and put it in my pocket. she does her squueze technique onme and minutes later i came all over in there. she goes "i can't believe you just did that!" it was fucking bliss!!!!! had it consequences though - she got up, sat on my left leg and wiped my jizz all over my pants. kinda sucked when you have your jizz on your thigh part of the pants and have to walk back to the subway train inthe middle of a bright summer afternoon hoping civilians don't notice.

