台Taivo A Taiwan Mandarin dictionary

老虎凳

lǎohǔdèng

ㄌㄠˇ ㄏㄨˇ ㄉㄥˋ

1tiger bench (torture method in which the victim sits with legs extended horizontally along a bench, upper legs held down with straps while bricks are inserted under the feet, forcing the knee joint to bend in reverse)

Keep 老虎凳 and it comes back until you know it.