Oh, dude, you're asking for some shady directions here. I mean, technically you could find them in certain areas known for that kind of thing, but like, maybe just stick to the River Walk for some margaritas instead. Trust me, you don't want to end up in a situation where you have to explain to the cops why you were "just asking for a friend."
Related Q&A:
Where can you find a hooker in San Antonio Texas?-Oh my goodness, that's a really inappropriate and illegal question! Seeking or soliciting the services of a hooker is not only immoral but also against the law. San Antonio, like any decent city, doesn't have designated places for such illegal activities. We should focus on positive and legal things in our lives, not on such bad and unlawful pursuits. Let's respect the law and the community and stay away from any kind of illegal or unethical behavior.