I seriously doubt ever getting one, not because of the pain, I do well with pain, but rather that once I get old, nobody should have to see that, including me! However, if I did get one, I would get it either right inside of the hip bone or straight back from that (right inside the hip on the back). It would either be:
a charging buffalo...not just ANY charging buffalo, THE charging buffalo. AKA the Buffalo Bills symbol.
or
a stop sign with 'halt' writtten in it. (bizarre but my last name is halt and growing up with the stop jokes it seems fit. Also, my 3 aunts and mom all have it so ya gotta have some sort of tradition!)
or
I'd find some random freckle on some random part of my body and get 2 circles to make ears to make a hidden mickey on me! Haha, ok, so maybe not but I would be highly ammused by it!
Again, seeing me getting one is highly unlikely because of the reason above but that doesn't mean that I haven't thought about it!