The labels have the character's name followed by 受 (uke), which means being the receptive or passive partner, or in BL slang means the bottom. Most underrated organizational system ever by the way. Please show this to anyone who claims that "unwoke" Japan doesn't "shoehorn queerness into everything".
I know this is only barely related but those osumatsu sextuplets are the best.
*Buttsextuplets.