look up any word, like the eiffel tower:
The anus. It resembles a ballon knot.
Her ballon-knot was so tight I couldn't get a pinky in there.
by poohbar January 31, 2010
the ballon knot is a term for the anus
"i pulled out of her ballon knot then stuffed it in her mouth"
by cornfed666 January 25, 2006