For AIBooru purposes, this tag refers to images where the breasts are noticeable, i.e. you should not use this tag to describe a flat-chested girl.
If unsure of the breast size, this tag can be used by itself as a catch-all tag, i.e. without the size modifier.
The following tags are aliased to this tag: boobs, breast, and tits (learn more).
The following tags implicate this tag: backboob, between_breasts, bouncing_breasts, breast_focus, breast_hold, breast_rest, breast_squeeze, breasts_apart, breasts_out, bursting_breasts, cleavage, cum_on_breasts, floating_breasts, gigantic_breasts, hanging_breasts, huge_breasts, large_breasts, medium_breasts, mole_on_breast, oppai_loli, perky_breasts, sagging_breasts, sideboob, small_breasts, unaligned_breasts, underboob, and veiny_breasts (learn more).