Lol, I discovered the exact same electro torture method than op only by myself when 16 or 17 (i'm 24). Often I freeze my nipples with deodorant spray before to get them more sensible.

I prefer DC and enjoy a lot my reduced train transformer, it gives more smooth sensations even it's kind of more aggressive for the body (nipples are peeling and navel is oozing for days which is a great part of the shame for me). I found AC too raw and less sustainable.

One or another : don't start.
Hope you will get peace op.