i have had to "fix" a couple proplapse. Here is how I did it.
1. ice cold water with lots of water. Not a paste but Ice cold water with lots of sugar fairly well dissolved. I sat for about 15 minutes and kept gently pouring the ice water over my baby.
2. Next take ky jelly and massage it back into where it needs to be. When I say massage, be gentle but be prepared to put some pressure behind it. First time I just rubbed like it would jump in, not so, you have to press about 3 times as much pressure as you would think.
3. After you get it in watch him carefully for the next couple days to make sure he doesn't proplapse again.
4. If you can't get it in, take these directions to your vet. The process is the same as a dog, cat or cow. The animal is just smaller.
If there is ONE protrusion it is his vent prolapsing. If there are TWO or if one or the other is coming out at a side angle then it is the hemipenes.
Can you please take a picture?
My advice is to buy some KY jelly lubricant and then rub some gently on the protrusion and gently try and push it back in.
If it is only coming out when he poops thats fine.
I don't think there is such a thing as a vent prolapse.??
Carol, I'm sure he meant intestinal prolapse but I believe the treatment is the same for intestinal prolapse as for hemipenile prolapse.
A bird's cloaca is referred to as vent--maybe he has some birds as pets, too