http://en.wikipedia.org/wiki/Erotic_electrostimulation
She may even ask for this in her stocking.
Look up Violet Wand, too- there are people who actually LIKE this stuff.
“Look up Violet Wand”
Man! I’ve got one of those! Found it at an antique store 25 years ago. Always been interested in neon, and it was too strange to pass up. Quack medicine thingie. I did once frighten an old girlfriend with it though!