the lower part of the digestive track adjacent the anus; the rectum
If you have rough anal sex then you may end up with a sore asstube for a while.
by real id guy June 07, 2009
Word used to describe an asshole when specifically suggesting that the person is the tube-like, shit-covered skin within the anus, rather than the air between it.
That guy just stole my seat! What an ass tube!
by Carton Jones December 16, 2008