The wiki for knees on chest says

When a subject in the image lies on their back and brings their knees to their chest.

but a lot of posts are tagged with it without the character being on their back. Is there a way for regular users to mass edit selected posts instead of editing each post one by one?

Also, I suppose it should implicate on back if we use that definition.

edit: unrelated, but there are 7 posts tagged japanese. It's fine to empty it, right?

Random examination of posts without the character being on their back (post #271141, post #367225, post #455911, post #457840, post #248844) indicates that knees_on_chest had been used by various contributors and janitors since 2008. So it seems like a wide-spread practice than a regular user mass edit.

Personally I feel that knees_on_chest should be aliased to knees_to_chest. Then various postions can be searched by combining knees_to_chest with the existing on_back, on_side, or sitting, provided there's a gardening step that add these tags in first before aliasing.

edit: Yeah, I think so. I cleaned up those 'japanese' tag by replacing with 'translation_request', and post #1395550 looks like a mistagging of 'japanese_clothes' with 'japanese' due to fast typing.

Agree with the proposed cleanup of having knees_on_chest become more generic knees_to_chest + position tags.