O.M.G.

Stands for Oversized Male Genitalia Syndrome. A genetic birth defect that grows the penis to absurd proportions. Every year, thousands of men are diagnosed with OMG. Sadly, most are banished to the fringes of society, victims of their own freakish length and girth.

Woman: So...let's see what you got...
Man: (Pulls down pants)
Woman: O.M.G.!
Man: What?
Woman: O.M.G.! You have Oversized Male Genitalia Syndrome!