You needn't worry at all about this event. In general the online information about STIs and oral sex is seriously overblown. Oral sex is safe sex, with low risk of transmission of all STIs and zero risk for some (including HIV) -- even for prolonged oral-penile contact to completion, including "deep throat" contact. This is because oral STIs aren't all that common; and when present they are not readily transmitted. For the extremely brief exposure you describe there is no risk at all. In my 50 years in the STI business I have never seen anyone with any STI after an event like yours. You don't need testing for anything; and if you have a regular partner, you can safely continue your usual sexual practices without fear of transmitting anything to her (or him).

I hope these comments are helpful. Let me know if anything isn't clear.

HHH, MD