Kitten with blood on penis - but it's not a bladder/urethra problem

Our kitten Derek is 6 months old. We took him to the vet when he was quite small with a bleeding penis.

The vet said it was external trauma (as opposed to illness) and either he or his sister must have bitten it.

Confusingly, the injury was hidden, i.e. inside the furry bit. - and difficult to bite!

The problem is, it's happened three times since (Most recently today).

It doesn't bother him, he's eating fine and playing normally - being cheeky, and it heals on its own. Are we wrong to assume it's just rough play and he'll grow out of it?

The vet is as puzzled as we are  - never seen anything like it.

I've found no similar stories on the internet.

Does anyone have ANY experience of something similar?  

Personally I have never heard of that happening - just from your own observations, do you see Derek & his sister rough-housing a lot?   Do you think it's possible that he's doing it to himself - do you see him licking himself down in that area frequently or anything?  Poor baby, that sounds unpleasant!  

We have three girl cats and one boy kitten, and two of the girl cats will bite the boy kittens privates... the third girl will have nothing to do with him.. He also tends to "play with it" a lot.  Never seen a boy kitten's willy before this cat, and you see his all the time (but it doesn't bleed).  So long as your kitten's is healing, I guess alls well that ends well.

They play, sometimes fight, and he cleans down there like normal- but I've never seen anything that would explain this! It must be something that happens when we are not around. I'll take him back to the vet but they'll just tell us to clean it and let it heal again.
i was just hoping someone had seen the same thing before as its a bit of a mystery!

My cat injured himself quite badly maybe because  he had pain connected with struvite crystals. My vet told me that they have never seen something similar. If you notice that the pee is very small and cat is licking his private parts more than normal maybe you should visit the vet. My cat had bitten his penis several times and had to wear e-collar for several months. Now his bladder is ok, he is on veterinary diet and constant visits to vet and he stopped to bite himself.

That's really interesting - that it could be self-harm in response to pain. Our vet didn't suggest that. He doesn't seem to have any urinary problems but if it happens again I'll take him back in. Glad to hear yours is getting better!