A or type mouth that smells of what is known as, ass. Butt Mouth can most certainly be a way of describing an animal, such as a dachshund, who by any means, licks its own ass hole, therefore giving off a disturbingly disgusting smelly breath which is best described as, butt.
That nasty wiener dog has the shittiest butt mouth!
by Dr. Buttikiss Maximus January 28, 2012
1 more definition
Any one that of or therefor who has, will, or is eating that of an butthole.
Tommy, i told you not eat my asshole out you buttmouth
by jermey September 18, 2003