Do watch for inflammation of the vent. The vent scale should sit flat and close completely. I recently took two ball pythons to the vet when I noticed them with their tails up all the time (not just when defecating) and both had problems.

In one case the vet thinks the snake got dehydrated (excessive ventilation in his cage) and he built up uric acid clumps and these are rough and irritate them when they go to the bathroom. He is on antibiotics to help him heal the vent infection and I’m soaking him regularly and have closed up the cage.

The other was full of a parasite called giardia (captive bred snake so I'm thinking from commercial mice), which apparently had overwhelmed her digestive track and caused irritation and infection. She is on antibiotics and Flagyl to treat the parasites.