Every time a guy performs oral sex on me he begins coughing excessively right after. do you think it could be hiv/std?

Lab draw necessary: It is not very clear why the guy begin coughing excessively right after. You may want to ask your sexual partner, maybe he can inform you further about that. I would advise you not to engage with unprotected sex unless you are in a monogamous relationship. It is a high risk of contracting hiv/hep c/std. There is no way to detect/confirm hiv/hepatitis c without lab, certain std may exhibit symptoms.