noun
air chair; wall sit
An exercise or prank where one mimics sitting in a chair without actual support, often against a wall.
体育の授業で空気椅子をやらされた。
We were made to do wall sits in PE class.
空気椅子は太ももに効くトレーニングだ。
The air chair is a training that works the thighs.
noun
chain of people sitting on laps
A party game or stunt where people sit in a circle on each other's laps, forming a self-supporting chain.
合宿で空気椅子をして遊んだ。
We played the lap-sitting chain game at the training camp.
Compound of 空気 (air) and 椅子 (chair), literally 'air chair'. The term describes the illusion of sitting without a real chair.