Welcome to our Forum.  Before I comment on your questions, a bit of context.  Questions which include statements like "is it possible...." cannot be answered with certainty, other than to say anything is possible.  Here in this Forum we provide information which is based on the combination of scientific study and data, along with out combined over 70 years of experience doing research and providing care to persons with and at risk for STIs.  New information is generated on a nearly daily basis and things that have never happened before happen.  Thus, you will find that the information that you will receive has more to do with probabilities and likelihoods than "possibilities".  While it is "possible" that you will be struck by a meteor falling from space while reading this, I can assure you that it is most unlikely.

Second, an error that many of our clients make is the assumption that all or even most exposures lead to transmission of infection.  That is not the case. In fact, STIs of all sorts, including HPV are only transmitted in a minority of exposures.  So, following any single exposure to a partner whose infection status is unknown, it is unlikely that the infection will be transmitted, both because of the FACT that most people do not have STIs and, even if they do, most exposures do not lead to infection.   While the per exposure risk for HPV infection is not well defined, I am confident it occurs with less than 20% of exposures.  Thus, the odds of infection following any single exposure are very low.

Now let's return to your question.  The activity you describe was VERY low risk for infection, mostly for the reasons I mentioned above.  HPV transmission is facilitated by friction and does not require open cuts or abrasions to occur.  The more friction, the more likely transmission is to occur even though that likelihood remains quite low.  This statement (about friction) related to both regular skin and mucous membranes.  The skin of the head of the penis tends to be thinner and more sensitive than skin on other parts of the body (including the shaft of the penis) and in uncircumcised men this skin is still thinner than in circumcised men but in both cases this is not a mucous membrane. For the male penis, the mucous membranes begin on the inside of the opening of the urethra as it enters the penis.  Tapping of the sort you describe is a very, very low risk event and should not worry you in terms of risk for HPV.

Finally, I would add that as you know, most unvaccinated persons will get HPV at some point in their sexual lifespans.  This is sot something to fret about- most such infections go on to resolve themselves over time (typically months) and even when they persist, they rarely evolve to become cancerous.  We urge our clients to put their (often internet-fueled) concerns about HPV aside, other than to get the HPV vaccine which is safe, highly effective and dramatically reduces the risk for HPV infections.  If you should get HPV, likewise, at present it is not something to worry about.

I hope these comments are helpful to you.  EWH