create implication mole_on_breast -> breasts
I just looked over the tags, especially covering mole_on_breast flat_chest and all posts are either having another female person or the flat vhest tag was not correctly applied (post #551433 and post #553767)
Anyways, since small_breasts do now imply breasts, there is this obstacle out of the way.
For flat chest (and if a male has a mole there), we could use mole_on_chest for example.