Asking her boyfriend to come over and help her fix a new piece of hardware was just an excuse to seduce him and finally enjoy their first anal sex. The lucky guy was so surprised at first cuz you don't usually expect your girlfriend to be an initiator when it comes to assfucking, but once he felt the tightness of that sweet chocolate hole there was no stopping him from banging it deep and hard till his girlfriend ended up begging for mercy.
