I'm really sorry this is happening to your beardie. That is definitely fecal matter, there may be some tissue under it but you need to get to a vet today or soak him like I suggested and use a Q-tip to gently break small bits off of the end. He might still make it but that has to come out. Try the Q-tip for now.
I agree, be very careful when trying to get parts of that broken off or worked out. It
absolutely has to come out so I definitely think a vet visit is needed as soon as possible.
It cannot feel good & you wouldn't want him to fully prolapse.
Let us know how he is doing.