Thanks, Teak. I am grateful for the prompt reply. I know you have helped many on this forum and elsewhere. Is there a scientific reason that I was never at risk other than the fact there are no documented cases? For example, was I never at risk because blood on blood contact requires a larger amount of blood than I described? Or because the razor cuts do not provide an effective entry into the blood stream? Or because HIV doesn't stay active long outside of the body? That is, what distinguishes my scenario from, say, someone's blood coming into contact with someone else's open cut?
You were never at risk. HIV is not transmitted by masturbation.