When a woman performs unwanted sexual acts on a man when he is passed out or on the verge of passing out due to drunkenness or intoxication. Most commonly performed by women who are unattractive or have questionable character.
Guy 1: Bro.. that gross Becca from that party chick totally melkoed me last night.
Guy 2: Dude, Becca melkos everyone! You should get tested..