make him swallow a cherry bomb
Carry a flathead screwdriver in your purse. They're legal for anyone to carry and it hurts like fuck when you're jabbed with one. Plus not very many people are gonna fuck with someone who's attacking them with a screwdriver. Like other people said, don't try to be fair. If you have to castrate a motherfucker to get your point across, do it.
Seriously, though, if you're not comfortable with a situation and there are people around, make the biggest scene you can. Scream, yell, hit, cuss, just go fucking nuts. If someone's just being a little creepy and not taking the hint, don't worry about hurting their feelings. In fact, wound them so badly emotionally that they're crying on the floor in a fetal position by the time you're halfway through.
Instead of pepper spray, get wasp spray! It hurts worse and can spray farther.
Did you try getting up and taking a different seat?
Life is like a book, in that the avoiding experiences is like skipping a page, and staying in on weekends is like skipping a chapter.
Just carry like a huge chain and if anyone tries anything, smash them up with it and then when the cops show up, just fasten it around your waist and be like oh this is just my belt constable
Yeah, I know. I think it's illegal to use for self-defense in most places, though.