dual fisting: a sexual move consisting of the insertion of one of the males fists into each of the females holes (anus and vagina)
jamaal: dude your hands smell like shit
guunter: yea man, its cause i pulled the mastadon on susie last night
a sexual move that is often considered the most awesomely brutal way to pleasure your woman. First, you have her turn around and bend over as you back away a good 20-30 fists. Then, you make a tight fist with your thumb on the inside (you'll find out why shortly). Then, you ram at her full speed, shoving your fist straight up her vagina, while crying out "MASTADON!!".
I just gave that chick the mastadon from 40 fists away!