Sayoko is the one who's face is covered on the blanket (left) Noi also has his face under the blanket (right)
Those two are mine
Gears and Ravioli (top and bottom) are Kayoss's
A kotatsu is a short table with a futon or blanket attached to it. A heating system is built under the table, and is most commonly used for sitting and sleeping, often during cold days since Japan has poor heating systems