Welcome to the Forum and thanks for your questions.  As you might imagine, there are no scientific studies to help us address your questions.  However, vast amounts of observational data in which persons engaged in mutual masturbation did not result in transmission of HIV or other STIs strongly suggest that the encounters you describe were safe sex.  You can be sure that during vigorous mutual masturbation encounters that there is indirect oral exposure on at least some occasion with genital secretions.   All STI's including HIV are transmitted almost entirely with DIRECT exposure in which the organisms are placed in direct contact with the site of infection.  Indirect transfer of genital secretions is not considered a risky activity.  Based on this, it seems most unlikely that your licking of the shaft of his penis and scrotum would put you at any meaning risk for infection.  Further, just to emphasize this point, from your post it appears that you do not know that he had masturbated before you got together, and if he did you have no idea of how long it was since that event that your encounter occurred.  This is certainly not an exposure that I would be concerned about even in the absence of specific data.  If you are concerned, testing is easy and I am confident that it would show that you were not infected but I would not even both doing that if I were in your situation.

I hope that this information is helpful to you. EWH