Dogfish come in two varieties...smooth dogfish and spiny dogfish...smooth dogs have sandpaper mouths and are most commonly caught in the late spring, summer. Spiny dogs also have sandpaper mouths but also have a wicked pointed spine on the dorsal fin..cant remember if they have them on the caudal fins as well...they typically like colder water and are found more commonly in the late fall, winter.
As far as stinging you, smooth dogs dont...spiny dogs dont sting either but if you get pricked by the spine/s, it'll hurt and may have something in them that could infect your body part that gets pricked...
Phil L