Do  you  use a swivel  when fishing with a curlytail wormn  to stop line twist ?

No, a properly rigged worm should not cause line twist. 

No swivel ever unless it's an inline spinner and even then I don't have the problems some have with line twist so I don't bother. No reason a worm should cause it. Might just need to respool if you are having problems with the line. 

Not so much to stop line twist or with curly tail worms, but I use them sometimes instead of sinkers when pseudo split shotting or mojo rigging, since I have a bunch of sizes of swivels from salt water fishing.

Only time I use a swivel is on a Carolina rig

I don't, but the only down side would be extra knots, and different type of cast.  I use a BC, though.  I do use them with spoons and in line spinners.

Only on a double fluke rig...

I only use a swivel with a C-Rig or a fluke.  

Why is everyone so against swivels? What harm can it possibly do?

Rig the  worm curl down .

tks all for replys