buttmallows 

The two cheeks making up one's ass. Buttocks.

Kathleen was too busy toasting her buttmallows by the fireplace to worry about the ringing phone.

buttmallows by Boozy Tang January 5, 2008

buttmallow 

Marshmallows that an extremely attractive female deficates when a man hits her G- Spot during sexual intercourse; may occasionally taste like cellery.

Dude, check this shit! When I was boning your sister last night, she came so hard she totally busted a buttmallow!

buttmallow by Thisus A. S. Yudonum April 22, 2009