Sexual act. Usually between two males, or a male and a very manly female with anal hair. One partner lays down on their stomach exposing their anus, the other starts from the Gooch or
Vagina and sniffs all the way to the Bum
Crack, possibly getting some shit stuck in his/her
nose.
Joanna the man woman was pleased when John
gave her a refresshing Snuffle
Bum. Although she acted disgusted.