桃もも尻じり

noun

bad at horse-riding; unsteady rider

Describes someone who cannot sit steadily on a horse and bounces or fidgets in the saddle. The image is of a peach-shaped bottom that won't stay still.

• 彼かれは桃もも尻じりで、乗じょう馬ばが苦にが手てだ。

  He's a peach-bottom—he's bad at horse-riding.

noun

fidgety person; restless person

Extended from the horse-riding sense: someone who can't sit still, constantly shifting or squirming. Often used humorously.

• あの子こは桃もも尻じりで、授じゅ業ぎょう中ちゅうもじっとしていられない。

  That kid is a fidget-bottom—he can't sit still even during class.