Also known as: あやとり, 翻花绳, 翻线戏, 실뜨기
A game played with a loop of String resulting in a cat's cradle between the fingers of two (or more) people.
On Pixiv, the tag パンツであやとり (panties' cat's cradle) is used to denote whenever one plays cat's cradle using her Panties; see Presenting Removed Panties for this.