I mean, it's kind of random. He doesn't just do it when he's in his enclosure. That video was right after I put him back in after cleaning his sopping wet towel because he knocked over his water bowl. Normally (I say that even though it's only been happening for the past 4-5 days) it's when I go to pick him up or put him down.
But your snake never had any major issues when he did that? You said he stopped after breeding season, did he do it every season?
When he did it months ago it wasn't so aggressive of a spasm. And it was only once.
No, I haven't had a fecal done on him. The vet only offered to prescribe pain meds but I denied it because I didn't think I could get him to take it and he didn't appear to be in pain in any way.