I found the perfect pajama shorts the other day.
The thing is, they're not technically shorts! They are, in fact, tapered cut boxers. I found a pair of blue and white printed ones mis-filed in the ladies pajama section of a thrift store, and I happily snapped them up because they were so cute.
And they fit better than any short pajama bottoms I've ever had. Because the leg openings are narrower than regular boxer shorts (and than those on pj shorts), they don't ride up or bunch. And while they're a cotton-polyester blend, they feel like 100% cotton.
I want about six more pairs since I don't want to sleep in anything else ever, so I googled 'tapered short boxer.' As far as I can tell, Jockey is the only company that makes such a thing, and they no longer make them in mens' size small (the size mine are). They are, however, $16 for two pairs on Amazon - definitely cheaper than pajama shorts from Target! I might compromise and order a pack of mediums to see how they fit.
and yes, I did just write an entire post about buying boxers from the thrift store. that's what the washing machine on hot is for!