Most female CSWs have no transmissible STD at any point in time, and it sounds like yours is especially unlikely to ve infected; most such persons are truthful about test results etc. And you had safe sex:  condoms are effective and oral sex is low risk. To your specific questions:

1) You were at very low risk for all STDs and probably zero risk for HIV, which has never been known to be transmitted mouth to penis; and most CSWs don't have HIV.

2) I would not advise PEP after such an exposure.

3) It is rarely necessary to be tested for any STD or HIV after any single exposure. Testing therefore is optional. Of course you are free to be tested for reassurance, even though you were at little or no risk. If you do it, you can have a urine test for gonorrhea and chlamydia 4-5 days after the exposure and blood tests for HIV and syphilis at 6 weeks. For sure you should not have any other tests -- avoid "comprehensive" test panels offered by many labs.

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

HHH, MD

Thankyou! for the response. However I have few more questions.

1) In the worst case scenario, what are the STI, I might have got infected in the scenario I mentioned. Also, what are the symptoms I have to look for, So that I can go for testing immediately on occurence of symptoms.

2) Can I have unprotected sex with my regular partner now or do I have to wait till the tests.

2) Yes, you can continue sex at home. If somehow I were in your situation, I would not be tested for anything and would continue unprotected sex with my wife with no worry about infecting her.

Thankyou! for the reply. I hav one final question regarding my exposure.

During the vaginal intercourse I observed that condom rim has moved from the base of penis shaft, but it was covering more than 60% of penile shaft and tip of the penis completely. At that time I have adjusted the condom and ptoceeded with the act. At last when ejaculated and withdrawn the penis condom was covering about 50% of the shaft and completley covering the tip and all the fluid is inside the condom. So , I think condom did not break. However, do i consider it as slip of condom.  I think it is a no risk exposure for HIV, but I am looking for your opinion which makes me feel better.

Thankyou! once again and I know this is my third and final question

That does indeed conclude this thread. Thanks for the thanks! Best wishes and stay safe.