Toasterhead is a label. It is used about punk males with heavy underarms (and a body to match!), lots of tattoos, preferrably some piercings and a fairly round facial type. (Goes with the body...)They usually have a good vibe attatched to them, they're not pissed off old punk dudes.
Benji Madden and most of the rest of the guys in Rancids "Fall Back Down" vid are Toasterheads.