Back Crack Fart

When a person (friend, family member, crush, boyfriend, etc) cracks a person's back by having a person lying on their stomach. They have the person laying on their stomach breathe in and on their breath out they push upward while applying force to the back. In this moment, while breathing out, this person lets out a fart.

Wow, I can't believe she back crack farted when he cracked her back.