
I can't see either of them coming to any harm. It could be just play or a dominance thing. I get that here with my dogs, but now all I say is no and they stop, I don't allow it either. I had a scare one time when 2 of my boston's were doing that( but not humping her back, male and female both fixed siblings) the female bit his penis and when he urinated I saw blood but not in the urine just at the top. Took him to the vet and had him looked at, He had 4 tiny puncture wounds down the shaft and that was bleeding. She told me it was O.k but not let them do that since he could really get hurt, I wasn't allowing it any how and now they don't do that any more. I never knew dogs did that until I seen them 2. It was like she was cleaning him, thats what I thought at first. Just thankful he's o.k and nothing to serious.