Today I had an encounter with a csw. We've had pretty intense chemistry after visiting her for a year now. But today things got even more intense. She performed unprotected oral on me. We had heavy frottage with my penis tip often rubbing up against her clitoris and inner labia. Even her vaginal opening. But mostly my shaft rubbed against her.

And where I'm most worried is that my tip went in a few times. Not full deep penetration. But at least the entire tip. I took it out right away, but again, I succumbed to the heat of the moment and the tip went in again. I can't say for how long, but the entire event took place over 30 minutes. And I doubt the insertion lasted more than 2 minutes (if that matters). 

Now I obviously completely regret all that I've done and am worried to bring any infections home. She tried to reassure me that she is clean. That she doesn't have a boyfriend or had unprotected with anyone else (I'll have to trust her). That she was checked a week or two ago and was clean. I am worried, but I remember reading both of you saying that usually csw don't have infections and when they say they are clean, chances are they are (correct me if I made that up in my head).

But what do you recommend I do in terms of testing and if this is an event that should cause me to be concerned.

Thank you again

While the encounter you describe was low risk, it was not no risk.  You are correct that most CSWs do not have STIs and as a rule, they tend to be better at testing and making sure they are not infected than the general population of people who may occasionally have casual sexual partners.  Receipt of unprotected oral sex puts you at low risk for acquisition of gonorrhea and your vaginal exposure puts you at risk for common STIs such as gonorrhea, chlamydia and trichomonas.  Penetration is penetration and therefore, if your partner had an STI, you were at risk for acquiring it although as I've already said, most CSWs do not have STIs and most single encounters do not result in transmission of infection. 

There are several approaches to testing.  The quickest and most direct way to be 100% sure you are not at risk is if you can arrange to have your CSW partner tested.  If her tests are negative, you are not at risk.  Persons with negative tests do not transmit infections.

 If you choose to test yourself (testing is always a personal decision), then you should wait 3-4 days until testing as testing too early carries a theoretical risk of missing an "incubating" infection.  Then, at that time the most important test you could get would be a urine test for gonorrhea, chlamydia and trich.  Other STIs such as HIV or syphilis are so uncommon that I do not feel that testing is essential but if you wish to test, testing for these infections is not conclusive until about 6 weeks following an exposure.  

I hope that this information is helpful.  EWH