mass update waist -> -waist
As per topic #12858, this tag isn't used for anything else than tag padding especially when used on posts like post #3269669, post #3279181 and post #3285216. I don't see any practical value in this tag being used other than maybe close-up posts focused around the waist area but that's about it, it doesn't help that there is no wiki either.
EDIT: The bulk update request #1850 (forum #152092) has been approved by @Hillside_Moose.
Updated by DanbooruBot