A character is so thick that it goes literally perpendicular (90 degrees) from waist to hips/thighs, but which isn't necessarily hyper but "volumptuous", "huge butt" just doesn't cut it. (blacklisting those would blacklist a bunch of good stuff too, because the tags are too vague/general)
Example:
https://e621.net/post/show/1803973/
(or half of sssonic2's gallery)
Suggestions:
ridiculous_thickness
perpendicular_hips and/or perpendicular_thighs
Updated by BlackLicorice