A person who's sole purpose in life is to be held upside down by their ankles and swept around like a broom so that their hair can soak up COPIOUS amounts of semen. Generally, Milk Mops also have erectile dysfunction and have yellow sandals on their feet.
"Hey man, did you hear that Ryan just became a Milk Mop?"
"OH NO I hope he will be okay, I wouldn't wanna wear yellow sandals"