Ok, so it's only a little more likely to cause the spread of HIV, two thumbs up from me!
However, that still doesn't address the fact that it's highly unlikely to result in a happy ending for the would-be rape victim, unless you seriously think a few hooks in the penis is going to stop anyone dead in the tracks. The rapist will grow exceptionally angry, become violent, and the little chance that existed in first place of survival for the victim will decrease further. This idea was pioneered years ago with the "Attack tampon" and never went anywhere from there because of criticisms such as these.
Seriously, put yourself in that mindset for just a second, you attempt to rape someone and are quite surprised to discover your penis has been pretty injured as a result. Remembering of course that you're quite likely already highly aggravated, I don't think it's likely that you're going to decide to call it a night and head home to lick your words (So to speak).
Unless it's something that is 100% guaranteed to stop the attacker (As in immobilise), it's just making it an even riskier situation.
Don't get me wrong, I'm all for resolving the problem, but I genuinely see this as something that would just create more problems. What about some sort of internal taser that delivers a near-fatal electric shock (And renders the attacker unconscious by doing so), instead of just mutilating a bit and pissing them off?
