I equally have never got a Tattoo for this reason, but I can understand why you would though, because the last tattoo I had done, did feel exactly like I was harming. It didn't trigger me or anything but I did think about it at the time, just as a matter of fact more than anything.
In a way I guess it could be seen as a productive form of self harm.
An interesting question would be, if the person getting the tattoo's intention is harm, could the tattoo artist be prosecuted for assisted harm or even GBH?