Why call him the mathematical masturbater? Because he is self-pleasuring w mathematics. Not that self-pleasuring is wrong, although he probably thinks it is, so maybe he will get a hint from this, but i doubt it. He is the only one in his magical numeric world. He is numerically abusing himself. It's just too bad he insists on having an audience. Maybe it's a cathartic experience for him. In that case, maybe the irritation is worth it.
SS