I think it's supposed to be her pussy muscles (kegels or whatever they're called) making movements. Supposedly, women can train their muscles to move like they're birthing, only now with a dick instead of a baby, increasing friction and thus sensation.
veyrall said: I think it's supposed to be her pussy muscles (kegels or whatever they're called) making movements. Supposedly, women can train their muscles to move like they're birthing, only now with a dick instead of a baby, increasing friction and thus sensation.