The lips of someone who likes a younger girl (bear with me), because their lips are magnetically attracted to the younger girls braces.
"Where's insert name here gone?"
"He's been magnetised to some 14 year olds face"
"Oh... She hot?"
"Shut up. Now."
"Man why were you just kissing that girl over there she's young enough to be your sister"
"Magnetic Lips mate... Can't keep my hands off a girl with braces"
"That could cause problems in your older years/court"