360 degree radar sense must freak them out. Sometimes Matt will just tap on Frank's shoulder and point out someone who thought they could stare just bc Frank's back was to them.
There are whole conspiracy theories about how Matt has super eyes that see through the back of his head. Matt whispers the best ones to Frank while wondering when these dumb fuckers will learn that swiveling your head around and palming your crotch is not at all discreet