Mong is when you are completely zoned out and can't hear anyone and look like you are focusing heavily on your own thought
Look at Jamie rudman he is monging out like mad
A cock mong is a person who loves cock and is identified as a mong
Boi 1: Bro, My friend Curtis is being such a little Cock Mong.
Boi 2: No way, my mum is such a cock mong as well.