You see all sorts of intense BDSM scenarious in porn where they use shock toys, but this right here is how they get used in my own play:
It’s basically just a lazy way to make your submissive jerk and twitch and beg — it takes zero effort and it does no harm and and you can do it as much as you want.
From the Visiting Faculty sex comic currently being published at Erotic Mad Science.
Electric nipple fireworks are the best fireworks:

He’s just informed her that he’s going to zap that nipple one hundred times in a row:
From Sex And Submission.
The nipple electrodes are specially engineered:


This is my new truth generator. You are going to be helping me test it extensively:

From a Tumblr: “Naked gardening is all good fun until you back into the electric deer fencing and get a rude shock!”
When they start to drool with pleasure, you know you’ve got the nipples wired properly:
From Wired Pussy via Bondage Blog.
If you’ve ever played with a TENS unit you’ll know it can really make your large muscle groups leap, contract, and even cramp at higher voltages. Tied like this with nowhere for the muscles to move, Skin Diamond is in for a world of hurt when the juice gets turned up:
More here, via ElectroSluts.
How much more is it going to hurt, when he turns on the electricity to the toothed alligator clamps on her labia?
From the Slave Factory BDSM comic by Feather (a Dofantasy comic.)