mouth frosting. the slightly thick, sweet fluid that rockets out of a man's hard schlong when excited to the point of orgasm. the mouth is the cake, the sweet cum is the mouth frosting. that is where the term "the icing on the cake" came from.
"krys has a pretty mouth, but it looks a whole lot prettier when I cum and it's coated in a rich layer of sweet mouth frosting"
"jane's mouth is like a fine french pastry, but that shit would only be complete after I freekin' lose my wad and cum, giving it a layer of gourmet mouth frosting"