Bitch duck is a cartoon character Peter Griffin from the television program Family Guy created for his show "Handiquacks". She likes to have no fun, and ruins others fun.
The ultimate insult. A person labeled as a "Bitchmilk" is one who is whiny, snobbish, complaining, pessimistic, cowardly, bitchy, really bitchy, and cunt-ish.
John was such a bitchmilk last night for not taking that last shot!
In most basic terms, the opposite of a badass. It describes one who, while drinking with friends, does not have the testicular fortitude to finish one's drink.