Help: Air Release Inside Snake?

[Bogertophis]

I've never had this happen before neither have I seen it/heard of it, but I would be shocked if a paper towel tube managed to break something... gently feel down the snake, feel for any breaks in the ribs if you are concerned. He could have also passed gas, it happens in all animals.

You misread the question- the OP was holding onto the snake & the snake was pulling forward against that tension.

...I was holding near him back end to support him because he was exiting the tube and going into his enclosure. As he was going through, I felt some release of something inside him....