![1girl absurdres background_text black_hair breasts commentary_request from_side grey_shirt highres leggings long_hair looking_at_viewer looking_to_the_side open_mouth original red_eyes shigupon shirt short_sleeves small_breasts solo top-down_bottom-up translation_request underboob white_background rating:s score:8 post #3948997](/cdn_image/preview/39/57/3957bf37b3f574474b8725bd8ea1cfc1.jpg)
This tag is meant to indicate a position where a person has the face down (close to the ground/bed/whatever surface the person is on) and the butt up in the air.
The following tags are aliased to this tag: face_down_ass_up, top-down-bottom-up, ass-up_head-down, top_down_bottom_up, and /tdbu (learn more).