I don't think you're going to find women interested in casual hookups. And if there was such a thing, I'm sure they've already have been having sex with whoever they wanted.

Don't use Tinder for that purpose. I haven't seen any girls on there looking for "casual hookups". I haven't seen any girls like that on OKCupid or PoF either. Or on any other site for that matter. The only thing that might be a possibility is a blatant site for that such as adultfriendfinder. I tried that site for all of 5 minutes before I called to get my money back. Its just a big scam. Basically, if there were women out there that just wanted casual sex, they have already been having it. Its too hard to find such a thing as a guy. I guess the best thing you could try would be to hookup in real life situations such as at a bar, but you're going to find really not-so-good people with who-knows-what kinds of problems, probably more problems than you're willing to deal with. Also, this sort of behavior is still generally shunned and widely not-accepted today. Good luck!