A fwomp is a situation in which one is dropping a deuce, but somehow manages to miss the water entirely, as the clump (The shit) hits the side of the toilet bowl.
Verb, To be unable to get an erection when having sexual relations with another person. Usually caused by alcohol (whiskey-dick) or just sheer nervousness. Can also be used in the plural form as fwomped.
Person 1: I had so much to drink last night, when I brought Shari back, I fwomped and was unable to fuck her.
Person 2: Dude, that sucks so much.