wrote this a while back for a new Dom hope it helps
Okay first electric play covers a lot of areas.
There is the tens unit which is probably the safest one to start with.
Then there is the violet wand, expensive but a world of different sensations are offered and if it is used carefully it is very safe.
The last one is electrical probes which I have never used but have studied.
The tens unit runs a small controlled current between 2 pads causing the muscles to contract and relax a very rapid rate. The area where the pads are to be placed should be shaved, and they must be stuck down securely a pad that comes loose will send a sharp stinging current. Most tens units come with 2 sets of pads and leads allowing 2 currents or the ability to cross the current at a particular spot.
I recommend placing them around the clit or nipple but not running across either. If she is comfortable with this you might try running one set across either but be careful with her clit. Most that I have played with can’t stand it running thru the clit and it can temporary loss of sensation. Find the kind that has controls that let you choose the style of impulse then it should have an intensity knob and a speed between impulses knob.
If you place the pads so that the current runs near the clit on either side of it, it is like a super vibrator and you can play with the strength and speed controls or set it and do other things to her away from them.
Now Violet Wands be sure to get one that has a ceramic center not the wax one. The wax melts and the wand becomes unstable. There are a lot of different attachments for most wands. I like the rake the best. When using it you need to keep it moving and the distance from the skin is very important either too close or to far away can cause burns.
Do not let her wear metal or if she has it on do not get the wand close to it, it will burn.
There is a tool that I haven’t gotten to use yet. The sub holds it allowing the current to run through her body any you can put on a glove to run over her body causing a different sensation.
The wands create a static electric charge but if held to far away they will arc to a small spot on the skin, which is painful like a super shock from walking across a wool rug and grabbing a metal door knob.
Just play with the different attachments you will find ones you both like.
As for the probes they take a machine similar to a tens unit. They apply a shock inside the body they are normally butt plugs, but there is some that is designed for the vagina.
The power unit also can be used with electric nipple clips which can be use on anything that can be clipped. The level of shock is much stronger then either of the other two when used properly.