Pucker Promise
When you make promise by inserting any body part into the other party's anus. They then pucker their asshole on said body part to seal the promise.
"Mason promise you wont roofie me tonight"
"I Pucker Promise I won't!"
"Ok!"
*sticks pinky in asshole*
*puckers asshole around pinky*
"There we go!"
"I Pucker Promise I won't!"
"Ok!"
*sticks pinky in asshole*
*puckers asshole around pinky*
"There we go!"