"buttmaster" is a new zealand slang term for someone that is considered to be very good at everything s/he tries. usually exceptionally good looking with chiseled features. a buttmaster is typically found inside a pub.
ben the polak is such a buttmaster that i've never seen him fail anything he has tried. he has chiseledgood looks too.
The state of having one's mouth smell, taste, and/or otherwise resemble the odorous qualities of a human anus. A colloquialism, does not require literal direct contact between the mouth and an anus.
(discussing timeline for leaving the house and the necessity to finish grooming first)
PERSON 1: Grooming is for squares. Let all the hairs grow an all the scents bring forth suffering to those within proximity.
PERSON 2: Ugh. I am not gonna go sit in a hot stuffy network closet with buttmouth. If nothing else I still have to smell it myself.