"Pick at your chode underneath the table and smear the underbutter on the chips and cards, you can use it against them later." "Aw dude, it smells like underbutter in here!" "How would you like my underbutter all over your face bitch?"
by Bam@cyberscrewed.tk December 17, 2006
The distinct area off the bottom that is at the lower part of the gluteus maximus. Usually the underbutt is highly regarded in terms of attractiveness. Often the underbutt is discovered at the beach when womens bikinis do not cover the whole area of the bottom.
by bicbiq December 22, 2008
Damn did you Ashley's shorts? Her underbutt is completely exposed, and it caused me to bust an instant nut.
by Tinnysman July 12, 2018
The second butt created below the original butt by tight underpants, where the elastic is doing all the work, under tight pants.
by tiffawiffa April 21, 2009