For tattoos specific to a particular Dom[me], laser tattoo removal is non-invasive and quite widely available, and as far as I understand it another tattoo could be put in the same or maybe similar place. Many tattoos are more generic, just "slave" for example. I read somewhere (probably in more than one place) that if requesting that a mark of ownership is tattooed, due consideration must be made to the ease/cost etc. of its removal. We all know, however, that at a particular moment in time when a sub is entralled to the point of wanting a mark of ownership, the mere thought of that ownership ending is out of scope.

VV