The JS guy told me that their current C4M collection uses Polyester/Elastane. Whereas the iconic JS Bulge thongs use Polyamide/Elastane. I'm also more a Polyamide kinda guy. These are currently the closest to the JS Bulge thong:
https://cut4men.com/fr/32-push-up
That said, I don't have many Polyester/Elastane items in general. Probably trying out a few and report back.
They also told me that the new C4M collection, that arrives next month, will use Polyamide/Elastane, that is more similar to the JS Bulge thongs. Looking forward when that comes out.
P.s. Love the discussion here