Stiff toothbrush
Sexual act where the male waits for the female to fall asleep, he gets a monster stiffy worked up, and attempts to simulate brushing the female's teeth. If completed, your wad is the toothpaste. The ultimate is if she never wakes up during the stiff toothbrush and your wad gets nice and crusty on her face by morning.
She's got my balls so blue I'm gonna give her a stiff toothbrush.