Cross between Chinese handcuffs and a wood chipper

They need one of these for men.

South African Dr. Sonnet Ehlers was on call one night four decades ago when a devastated rape victim walked in. Her eyes were lifeless; she was like a breathing corpse.
"She looked at me and said, 'If only I had teeth down there,'" recalled Ehlers, who was a 20-year-old medical researcher at the time. "I promised her I'd do something to help people like her one day." Forty years later, Rape-aXe was born.
...
The woman inserts the latex condom like a tampon. Jagged rows of teeth-like hooks line its inside and attach on a man's penis during penetration, Ehlers said.
Once it lodges, only a doctor can remove it -- a procedure Ehlers hopes will be done with authorities on standby to make an arrest. "It hurts, he cannot pee and walk when it's on," she said. "If he tries to remove it, it will clasp even tighter... however, it doesn't break the skin, and there's no danger of fluid exposure."

CNN

I support anything that hurts rapists, but this just has bad idea written all over it. Besides, it only works on the first guy as far as I can tell. So, it isn't perfect. Nice idea though.