When you take a puff of a blunt incorrectly, making it so moist that it leaves a fragment of a tobacco leaf stain on your tooth. If the leaf fragment sticks to your lip, it's blunt lip.
Smoker 1: Dude why you treatin the L like a god damn lollipop? Now you got fuckin blunt tooth"
Smoker 2: *Checks his tooth on his phone camera* Aw shit you're right, this thing is fuckin saturated