How about Frisk from Undertale getting electrocuted in an electric chair? Electrodes can be one metal helmet and one wire with a metal plug that's stuffed into her vagina. Both are wired to a large generator in the background.
She's strapped to the chair with lots of heavy leather straps, and is either nude or wearing unzipped cargo shorts and nothing else.
She's crying heavily at the beginning of the scene, then the electricity starts. Make it semi-realistic, so no crazy arcs of electricity but still some sparks and make her convulsions extremely intense. Show her convulsing and steaming, then cut to a close-up of her crotch briefly as she wets herself, then a close-up of her face as it's twisted into a horrifying expression by the electricity - eyes bulging, teeth clenched, mouth foaming, nose bleeding.

If Frisk isn't a character you want, then just make it an emo girl with short hair. And if you don't want to do the wetting then you can skip that part!

If you want you can also add electrodes to her nipples, or other parts of her body like her wrists and feet.

You're also free to make it as gruesome as you wish with burning skin and bleeding from her mouth and such. You could even make her eyes burst like overheated water balloons. But no pressure.