Control thumb

A method of controlling aspects such as tempo, depth, pleasure/pain, and orgasm of a woman by inserting the thumb tip of your dominant hand into her asshole and putting you fingers towards her back as if to grab her by the inside of her ass while fucking her pussy from behind.

Ashley yelled that she wanted John to go harder and deeper, so he took his right hand off her hips and used his control thumb. She immediately stopped telling him what to do and went along with however John decided to treat her in that position.