A butt slam is an intentional physical strike using the buttocks to hit another - this may be done by the attacker thrusting backwards, hip checking, or dropping butt first onto their target. A butt slam often leads into the target character being crushed under their attacker's butt or between the butt and a wall. Cracks or even a crater may be shown to imply an exaggerated amount of force from the butt striking the ground or walls.
Butt smothering involves a character having their face covered by another's butt. Most of, or their entire head, might be buried between the butt cheeks of the character smothering them. A character can be smothered and crushed under a butt at the same time. If a character is being sat on, but their head is not being pushed into the buttocks or between the buttocks, use butt crush instead of butt smother. Facesitting, unlike smothering, slamming, or crushing, doesn't involve any implied harm or discomfort from the character being sat on, and the character is able to breathe. A character being facesat usually performs rimming, cunnilingus, ball licking or fellatio on the character sitting on them.