Not sure what it is? Anyone else?

Ok well my SO and I for the past 2-3 months have been having sex and first it was him having small paper like cuts on the back of his penis sorry TMI and this past 2 weeks or so I've started to get them too we both have been checked and tested and everything is fine we are both healthy I'm just curious if it happens to anyone else ? Or if someone knows what it is Help Please