noun
fan of an entire group; group stan
Idol-fandom slang: supporting every member of a group equally, rather than having a single favorite. Often contrasted with 単推し (tan'oshi, 'single-member fan').
私は特定のメンバーじゃなくて、箱推しです。
I'm not a fan of a specific member; I'm a fan of the whole group.
箱推しだから、誰がセンターでも嬉しい。
Since I'm a group stan, I'm happy no matter who is the center.