Mop butt is the act of getting a mop shoved up your ass.
Omg did you hear that Tyler got mop butted?
a dance you do when you are around your friends... has to do with the the flags gurls keep in their purses... something you laugh about till death
i.e. Do you still have the dirty mop?
One who's extremely annoying and has no social life whatsoever. One who's extremely irritating and talentless and has a reputation for being a thot.
Felicia: Why you gotta be such a bitch sometimes?
Felicity: Why you gotta be a milleniul ass mop?