Why does his blanket say poopy friends!? http://www.mangago.zone/read-manga/itoshi_no_nek...

Haha that's cute

I think it's because they can't use Snoopy for copyright reasons ^v^
Probably Kei-chan bought it... he likes cute things, like that seal thing Kyuu, and that anago plushies, and Mii-kun... :p