A buttwink is when a person flexes their anal sphincter, causing their anus to visibly contract, effectively "winking" with their asshole. Buttwinking can be performed as an obscene gesture, or in a sexual context it can be either a sign of affection or a greeting.
To buttwink, simply use the same muscles used to defecate to flex your anus.
This act should not be confused with mooning (merely exposing your anus) since buttwinking is considerably more rude.
As Sensei Doug walked to his dojo, the rude employees of a strip mall store lowered their drawers, pointed their behinds towards the window, and contracted their assholes to buttwink at the passing martial artist.
Alternate spelling for the name of the 43rd President of the United States, preferred in all usages worldwide by everyone remotely familiar with the man and poised to surplant the archaic contemporary spelling in future histories. Origin unknown, though widely believed to have been coined by his mother for its obvious descriptive accuracy.
Also: derogatory slang nickname used to imply that the subject has similarly inferior qualities to the namesake.
His "Mission Accomplished" speech, where he claimed premature victory in the earliest days of his war on Iraq, marked a defining moment in the presidency of George W. Buttwipe.
Yo, I seen your little brother sticking crayons up his ass like he be George W. Buttwipe — no, don't taze me, bro! Ow! Ouch! I'm sorry, yo, I ain't mean it! Ow! Stop dammit I said I'm sorry! OWWWW!