I have a 2yr old pit he's not fixed and just recently mated with a female. She's not here anymore. Well he ran away overnite and when he came back I noticed he was bleeding from his penis. It's a good bit of blood. He stained the blanket that was in his bed and it continues to drip. It's a slow but steady drip. Any ideas on what it could be. Ive read that it could either be an injury or prostate disease just seeing if there are any other ideas.

Any type of blood on an animal should be checked by a vet.

There's no way for us to even guess, even a vet couldn't guess online.

You'll need to go to the vet, asap. In fact, if it's late where you are call around and find an emergency vet in your area. If it's a lot of blood your shouldn't wait until tomorrow.