Snide Rump
Noun
(From the latin Snideous Rumpous Horrendous)

1. A sub-standard or disappointing sexual performance.

2. A person with a know history of sub-standard or disappointing sexual performance.
The girl was a poorly experienced bunk up, much akin to a sack of spuds. Failing to participate to a satisfactory level, she was under par in the beauty department, had a fell tounge and her boat race was just fuckin retarded. All in all, a real snide rump.