You should not depend on this method of keeping. Things can and will go wrong when dealing with live animals and you will need secondary housing options if it becomes necessary. Not all animals are appropriate for cohabitation, so please research and know your species. My experience is with Gonyosoma oxycephalum, the “Red-tailed Green Rat Snake”.
Tip #1: Know the signs of stress
If you are noticing your snake constantly running, nose rubbing, not feeding, etc., it is time to reassess.
Tip #2: Multiple hides on multiple sides
You’re going to want multiple hides in a wide variety because your animals will want to be able to get away from each other and from you. I suggest different heights and sizes.
Another thing to think about is competition for thermoregulation. I run my Gonyosoma at ambient temps but if you’re using hot spots it may be a good idea to have two, which may require an extra large enclosure.
Tip #3: Strategic feeding
I have found that most of my Gonyosoma are drop feeders and gently grab and run when they think no one is looking, though I have a few that are very food motivation.
What I have found works best for me are closing hides with doors that you can shut when the snake is inside. If my drop feeder is in the hide, I toss in some food and shut the door. If no one is in a hide, the food motivated will barrel right into a hide when I throw their meal in. I then close the door and feed the other.
I used some boxes I found made by Herpcult that work really well but you can make some out of cork tube and PVC end caps and some foam seal.
Tip #4: Multiple water bowls
I use smaller water bowls for Gonyos as they tend to want to sit in them and are susceptible to skin issues. That being said, they are not the only snakes that like to hang out in water bowls so you don’t want one snake sitting in a bowel deterring the others from drinking.
Tip #5: Know when to quit!
Cohabitation will not work with most species and even species that on paper should work out, it may not. So you NEED to have a backup plan. I have had really good luck with this method with this specific species and these tricks.