Jeff, with my tat it wasn't the inside of the elbow that hurt but more the area that doesn't have much cusioning, in my case the shoulder. At the top, right on the bone, now that's murder!!! I would guess it would be the same as the elbow and wrist, yikes! I don't know if I'd be able to do it again, I still remember the pain and it's been 7 years! The inside of the arm right below the armpit is also pretty tough... Was only a partial half sleeve and it took 15 hours!
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