Will an STD appear immediately after receiving oral sex for an hour and manifest in burning while urinating? I'm a female. No other symptoms.

Varies. It may take a few days. Do you have any sores? Are you able to urinate? Herpes can sometimes cause urinary burning and even difficulty urinating. Herpes type i (cold sores) can be spread to genitalia during oral sex. Gonorrhea and chlamydia usually infect the cervix. Syphyllis is usually painless. Other bacteria like gardnerella can cause non std vaginitis. So can yeast. Best be examined!