I don't know how Goodras sleep honestly, but I like to think they curl up somehow, since their design is so curly already.

He's cuddling a pillow because I do the same thing. Sometimes (and keep this between you and me) I cuddle with a Goodra plush I have (one of many poke plushes of course).

Also a (possibly) fun fact: The tailhole in night diapers for dragons/other big tailed pokemon are at the bottom of the diaper between the legs rather than at the back, since they don't need to hold their tail at a 90 degree angle when sleeping. Next time you see a diapered dragon, take note of where the tailhole is!

(Day 1: Favorite Pokemon)