This is a fucking based fetish indeed, looong time that I am into this, I am surprised that this thread is still going, and that it took some time for a thread focused on this to be made here.
Honest opinion on why I find this shit hot: At least for me the pelvic curtain thing really invokes some sort of sexually-primitive atmosphere, makes the women wearing it look like ancient Babylonian/Roman/Egyptian fertility priestesses in a sex temple/dungeon/bathhouse that are waiting to be fucked in every single hole at a giant ritual orgy in the name of Inanna/Aphrodite.
Just like in the last "historical porn" thread on /aco/ and "Impractical Clothing" thread here on /e/ that had fertility goddesses, belly dancers, sacred prostitutes, and all of that awesome underrated stuff.