Normal or not?

Hello there, my dogs penis has a dark tip on the end of it. It’s round, like a ball, he doesn’t act in pain at all when it’s touched or evaluated. He’s 9 going on 10 soon this summer. He acts normal, pee’s fine, no change in his bowels, is this just something that happens with age?

Hello.   It is a fact universally acknowledged that painless skin lumps can often sill be cancer, so don't let the painlessness of the situation put you off.   This needs to be shown to your vet who will have a good luck at its position on the penis and may help you to come with a plan to identify the lump while it's relatively small.