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Oral sex. Most forms of unprotected penetrative sex giving and receiving oral sex is almost the lowest risk. With regard to HIV the estimated risk for acquiring HIV from performing oral sex on an untreated, HIV infected person is less than one infection per 10,00o sex acts. The risk for acquisition of HIV from receipt of oral sex is even lower. There’s never been a case of HIV proven to have been acquired from receiving oral sex from an infected partner.  With respect to other STI’s, the risk of acquiring and STI for giving or receiving STI is relatively low.  There is close to no risk of acquiring HSV-1 from performing oral sex on a partner, even if that person does have genital herpes. Similarly, the risk of acquiring gonorrhea is quite low.

Condoms. Condoms are highly effective for reducing risk of acquisition of HIV, and for other STI‘s. When used throughout a sexual encounter, a Condom, virtually eliminates the risk of HIV as long as the condom does not break. FYI, when condoms break, they break wide open leaving no doubt that it has failed and there is no reason for concern that a condom may have failed if it appears intact at the end of a sex act. 

Finally, let me urge you to test. It is important for me to point out to you the testing will not change whether or not you are infected, and it is unlikely that you are. On the other hand, when persons are at risk, test, and discover that they have been infected, that knowledge gives them the opportunity to take steps to address the problem. There are no STI‘s, including HIV, which cannot be treated.  Worrying about a possible positive test, particularly for someone who is at close to no risk for having an STI such as yourself is nonsensical. I urge you to go and get tested. I am confident the results will be negative and will help to address your anxiety. EWH.

I just wanted to follow up.  8 days after receiving the very short unprotected oral sex, I was urine tested for gonorrhea, trich, and chlamydia all negative, gram-negative urine negative and dipstick test all negative no wbc.

Are these tests quite reliable at only 8 days post exposure?

Should I worry about NGU? At about 3 weeks after encounter, I've felt a kind of wetness at penis tip but only seen clear discharge once or twice. No real pain on urination, minor irritation maybe?

After more reading here, I imagine it's probably just anxiety and I am hyperfocused on my genitals? Chances good that I can return to having sex?

Your tests prove that you do not have a transmissible form of NGU- I would not worry further.  A small amount of detectable urethral discharge is normal if you look hard enough.  

You are in the clear.  I would not worry about resuming unprotected sex with your regular partner.  EWH