He doesn't stop slam dancing, the form of it just changes a little as he demonstrates, first changing into a near-200 pound rottweiler, then further shifts into... well, its still a rottweiler, but its about the size of a grizzly bear... which is currently slamming into the walls and bouncing around her in time with the non-existent music.

A few moments later he shifts back, keeping with the rhythm.

"Yup, born 100 percent junkyard dog. Not a changeling - a werewolf. The ass-kicking, Earth-saving kind, not the 'eats people on the full moon' kind." he explains.