Bro, you can rest assured and you don't need to look for someone who will do this fetish. Otherwise, you will find a prostitute or an unfavorable experience. I lived in S?o Paulo for a short time (only one year), but I already had good experiences. My tip is to have a normal relationship with the woman without mentioning the fetish by message and when you are in person, be direct. As I also know that it is our custom make the "gringo" happy, this will be easier than you think. I can tell you that the hardest thing will be not getting good experiences! Enjoy S?o Paulo!