noun
futon steaming; burying someone under a futon
A playful or punitive act of trapping someone under a futon, often by sitting on it or wrapping them tightly, causing heat and discomfort. Sometimes used as a prank or in comedic contexts.
子供の頃、兄によく布団蒸しにされた。
When I was a child, my older brother often trapped me under the futon.
布団蒸しは、夏場は特に暑くてたまらない。
Being buried under a futon is unbearably hot, especially in summer.
Compound of 布団 (futon) and 蒸し (steaming), from the verb 蒸す (to steam). The word evokes the sensation of being steamed inside a futon.