I would remove the paper towel from the lid and replace it with something slick so he has no motivation to hang out up there or try to shed from there. I've never used paper towel as a cling surface and would personally want to use something with more texture for this species. Shelf liner is great. They make grated ones and they are cheap and can be bought at home stores like Home Deput. It is easy to cut and glue in place and makes a great grip surface. Plus, you can wash/whipe it off so I would imagine it would be far cleaner than paper towels that can get gunky over time.
There are a number of species that purposely raise their abdomens but Chinese mantises are not one of them. The fact they lack the mechanics and control to lift in that section is probably one of the reasons they are in part at a higher risk at getting a bad crease right there.
This species is not supposed to have a crease. He was saying it happens in other species too.
Oops miss read his post. I'm not familiar with the specifics of that species so when he worded it that they do it naturally I thought he meant they were lifting their rears on their own like say a boxer mantis might.
You can turn the cage but keep in mind this species likes to move about so if their isn't much easy to cling to options yet a lot of room in the cage the mantis might end up doing a lot of frantic wander/sliding on the slicker surfaced walls. I would create a mostly vertical sides for gripping and future shedding. Ideally you want his abdomen to not be flipped over his back while he is relaxing in the cage. It really doesn't matter which way he is facing as long as this is the case. When he does go to shed however he will be facing down. Keep in mind you should really have 3x his current body length in hight to make sure he has enough room when he goes to drop down from his skin.
