Thank you for your inquiry. From what we gather from the question, you were asking about the risk of acquiring HIV after performing oral sex without a barrier and potential contact of semen to your anus after penile rubbing occurred. From the information given, this scenario is determined to be Low Risk (evidence of transmission occurs through these activities when certain conditions are met).
The scenario mentioned above could meet the three components of the transmission equation. It could satisfy the equation because performing oral sex without a barrier could allow direct access of HIV-containing bodily fluids (pre-cum & semen) to your bloodstream through the mucosal membranes in your mouth. Please note that the risk assessment is not based off of potential contact/rubbing between their penis and your buttock/anus. Since there was no penetration, there would be exposure to oxygen, which would render the HIV virus inactive.
Recommendation: Refer to a health care provider for HIV testing and completely conclusive HIV testing outside of the window period (3 months post-exposure).
AIDS Vancouver Helpline/Online, Marie
If you are satisfied with the Helpline service, please consider Donating.