Hello, and thank you for your services.  Here goes:

3/11 I saw a reputable CSW, one I have seen before. Protected intercourse, unprotected oral and finished in her mouth. Cunnilingus for a few minutes. 3/23 saw two CSW's (threesome) that I had not seen before, but were well reviewed. Protected intercourse, unprotected oral from both, some cunnilingus. 3/29 urine tested (NAAT) for chlamydia/gonorrhea (via STDcheck/Labcorp). Both resulted as negative early this morning. I have been noticing some intermittent discomfort when urinating the last few days.  Today the burning is a little worse. I am now noticing some redness and inflammation at the tip. There has been no penile discharge at any point or swelling of testicles. I admit to some anxiety and hyper-examination with exposures in the past, but that usually disappears with a negative test. I've read through many questions on this forum, and am hoping you can confirm/clarify the following: 1) I should have faith in my test results, and did not test too early- I believe I read that I can expect accuracy when testing 6 days post oral exposure for these two STI's? 2) This was a low risk exposure. 3) NGU possibly? Do my symptoms line up with this? I have had one before (4 years ago) that felt similar, though there was no redness/inflammation of the tip. Is ther anything else I am not considering? 4) Should I avoid unprotected sex with my partner considering the above?

Welcome to the Forum.  Thanks for your questions and your implied confidence in our service.  I'll be glad to comment.  The encounters you describe were low but not no risk.  As you probably already know, your risk for any STI from cunnilingus and condom protected vaginal sex are close to zero.  There is a mall risk of STI from receipt of unprotected oral sex.  You have reliably proven that you do not have gonorrhea or chlamydia- your test results are entirely reliable and do not need repeating.  As I think you know however, occasionally persons receiving oral sex can suffer a rearrangement of the bacteria present in the urethra causing non-chlamydia NGU.  This process does not represent a threat to partners' health and may go away without treatment but also responds well to treatment for NGU.  Additional comments related to your questions below:---

Thank you so much for the reply.

I meant to say is this a symptom that is sometime present in NGU? 

Yes, the discharge is certainly consistent with NGU.  This does not change my assessment however.  I think NGU treatment would serve you well.  EWH---

Thank you. Last question…when I did the urine test for chlamydia/gonorrhea: does it matter that I did a mid-stream catch of the urine (I let some out before the specimen), or is the the test so sensitive it doesn’t matter?

The test is so sensitive that while not optimal, your results are reliable and should be believed.---