Fire up your smoker for smoking at 250 F. I prefer a lighter wood, such as apple or peach, but you can use a stronger wood such as hickory.
Score the bologna chubb using a sharp knife. Make the cuts 1/4" - 1/2" deep. Use any pattern you want. If you don't score it the bologna will crack or pop open as it smokes.
Rub the chubb liberally with mustard. Get in there, get your hands dirty. I find it easiest to stand the chubb on one end (which is why I don't use a full-sized one).
Sprinkle the rub liberally all over the chubb. More is better here, so don't be shy with the rub.
Transfer the chubb to your smoker and smoke for 3 to 3 1/2 hours.
Remove the chubb and let rest for 15 minutes before slicing.