expression, noun
something spread out widely; something taking a lot of space
Rare, humorous idiomatic expression literally meaning 'eight tatami mats of a raccoon dog's scrotum', used to describe something that is spread out or takes up a lot of room. Often used in a joking or exaggerated manner.
彼の荷物は狸の金玉八畳敷きだ。
His luggage is spread out all over the place.
会議の資料が机の上に狸の金玉八畳敷きになっている。
The meeting materials are taking up a huge amount of space on the desk.
From the folkloric image of a raccoon dog (tanuki) with large testicles, humorously exaggerated to cover eight tatami mats. The exact origin is uncertain, but it plays on the tanuki's legendary association with oversized scrotums in Japanese folklore.