(noun) To
masturbate vigorously, while putting 3 fingers in your
anus. More than 3 fingers do not constitute a fassbender.
This
type of masturbation tries to explain the sexual conflict Michael Fassbender put himself into in the movie "Shame", as he engaged intercourse with both male and female partners.
1. "After that
girl rejected me, I went home and had a fassbender, while I was
crying and eating ice
cream."
2. "Hey guys! Let's watch The Expendables and have multiple fassbenders!"