The throbbing, oversized lips of a STD infected mouth. Usually received from putting your mouth on a muffin dick or a vagina muffin (see my definitions for these). They hurt like a bitch and people won't understand what the fuck you're saying. Muffinlips cannot be cured.
"Hey dude I licked my girls vadge and now my lips hurt" "I can't understand you but fuck I think you have muffinlips."
is the rapidly spreading disese that makes one addicted to muffins..worse than any type of drug. Muffintitus can make you bankrupt from spending all your money on muffins. Usually the top of the muffin is wanted the most.