German for "double fist". Colloquially used to describe the act of insterting two fists into the same orifice such as the vagina or anus.
The term retains it's German origins as it implies a far more brutal treatment to the more conventional practices of fisting.
Similarly it is used within the Metal culture to indicate aviolent arousal to someone/thing or to express a distaste for someone/something, depending on context. (See example two).
1. Hrafvnir doppelfausted Mary whilst she was chained to the bathroom floor. The screams were amazing, i think she's starting to like it these days.
2. "I'd doppelfaust that girl over there!" or alternatively: "look at that hige brutess over yonder, she needs a good doppefausting in her mouth!"