After arousing your girlfriends sexual interests, you forcibly shove half of your clenched fist up her ass (hence the "quarter", since a "full" would be both fists), whilst simultaneously ejaculating into her anus.
The act of a mexican and a white guy performing disturbing, disgusting, vulgar and raunchy activities within a sleeping bag.
EX.
Friend: Hey did you hear what he did this weekend when he went to spend the night?
Friend2: No what?
Friend: they did the Dirty Bean & Cheese Burrito.
Friend2: Fags
When a uncircumcised male partner allows smegma (cheese) to build up in his foreskin and presses or docks his foreskin to a partners anus to allow them to express flatulence (fart), inflating the foreskin and mixing the flatus with the smegma. The mixture of gasses and smegma creates a stench and alters the smegma in a way the resembles aged cheese - according to those who taste it afterwards.
I ain't bathed in 6 days, baby and you are sounding' mighty gassy. Get over here and pucker your sweet asshole to daddy's uncut pecker so we can age the cheese.. and bring the crackers.