My boyfriend gets a red rash on the base of his penis after sex. We do not use condoms , but do use lube. We have both been tested and are negative for any STDS. He was told it could be a yeast infection , so he used cream and we didn t have sex for a little while. It seems toget better, but happened again after we had sex again. He uses baby powder and washes after sex, so we are at a loss to what it is? He says it s never happened before, it s not possible he s allergic to me is it?? Please help!