A person who does a lot of talking but never says anything. While this occurs their jaw flaps closely resembling that of a Muppet. In some cases the person in question may even resemble a Muppet or Sesame Street character.
That fool Kevin keeps flapping his jaw, he's a real muppethead.
A oral sex position where the man grabs the woman and vigorously has sex with the woman's mouth. This goes on until she goes googly-bug eyed and flails her arms around above her head helplessly in protest often making a "Mahyaaaaaahhhhhhhhh" muffled sound similar to Kermit the frog.