The lower portion of the male nutsack which typcially is judged by where the nuts are presiding. Depending on the mood one's "Gigglesac" region is usually the area of the bag containing the nuts. This portion can be stimulated by even the smallest of accents causing a slight giggle.
I got chills as the chipmunk graced the underside of my gigglesac.
by Wizard October 29, 2003