Samberg and Hader are at a party where everyone and everything is a literal representation of a slang term (i.e., a "serial rapist" (Forte) is shown having sex with a box of cereal, a group of "motherfuckers" are men with their mothers, a group of "sons of bitches" are a litter of puppies, a "numbnuts" is a man (John Lutz) shown sitting on a block of ice with his pants around his ankles, a group of "jokers" are dressed as different incarnations of The Joker from The Dark Knight, a knucklehead is a hand with plastic eyes glued on it, etc). When Samberg and Hader discover "two douchebags", however, it's revealed that they're looking at themselves in a mirror.
The bit uses almost the entire cast (plus some) including Kenan Thompson, Lutz from "30 Rock," Fred Armisen, puppies, Will Forte, Jason Sudeikis, and Casey Wilson.
Rockefeller Center New York City, NY