Mashing Cakes
To mash cakes means bumping uglies, swaping gravy, or doing the no pants dance. Can be used in past tense and appreviated ex."we mashed"
If you bring home a drunk college girl from a keg party, your probably gonna end up mashing cakes.
Mashed up Dundee cake
The disastrous results of shitting yourself and seeing what the contents of your undergarments look like
Egad I've got 3 and 3/4 lbs of mashed up Dundee cake in the seat of my pants right now