www.e-stim.net

I use copper wire loops on the outside how about in the urethra
is there any pros/cons for using it inside...

I use sounds make it more intense

I would be very nervous about inserting copper wire into the urethra. It would corrode quickly and some of that may rub off in there. Getting the copper polished enough to insert would be difficult and keeping it polished enough would also be difficult because of how soft it is. Aluminum would be better and cheaper, but 316 stainless steel is actually approved for medical use.

I opted not to...
what guage of copper wire has the least resistance...the larger or smaller...

Larger wire diameter has less resistance.

thanks I can never keep it straight