背せ中なかスイッチ

noun

imaginary switch on a baby's back that makes it cry when put down

Jocular term used among parents to describe the phenomenon where a baby who seems sound asleep starts crying the moment they are laid in bed, as if a switch on their back is activated.

• やっと寝ねたと思おもって布ふ団とんに置おいたら、背せ中なかスイッチが入はいって泣なき出だした。

  Just when I thought the baby had finally fallen asleep and laid them on the futon, the back switch flipped and they started crying.

• 背せ中なかスイッチが敏びん感かんな赤あかちゃんで、置おくとすぐ起おきちゃう。

  My baby has a sensitive back switch and wakes up the moment I put them down.