It's digging up his anal to find an escape route, that's what mouse/rat do, find light. They will dig/pierce through dark stuff just to find light!
In an act referred to as Gerbiling, male homosexuals will sometimes use rodentia (mouse, hamster, gerbil) as an autoeroticism adjunct. They place the small (defanged, and declawed) animal into a empty toilet paper roll, then insert one end of it into their own rectum. They expose the remaining end to an open flame (generally a lit cigarette lighter*), compelling the frightened animal to instinctively move away from the flame threat and directly into the anus. Once inside, the perpetrator would remove the tube and clamp down with his anal sphincter, preventing the rodent from escape. As the animal is slowly asphyxiated and thrashes about looking for a means of escape, the perpetrator masturbates with a heightened sense of pleasure from the frantic movements of the dying animal. This guy should be prosecuted for cruelty to animals. But honestly, in this day and age of open sex, porn, sexual aids, and such; why can't someone manufacture a furry little vibrator that writhes like a dying mouse. I'm sure the technology is already available. *Note: using an open flame in this regard may be extremely dangerous, as the colon is a potential source of highly flammable methane.
