食べてすぐ寝ると牛になる（たべてすぐねるとうしになる）

Japanese vocabulary

Meaning: do not go lie down after eating (because it is considered rude); if you lie down soon after eating, you will become a cow

See it used in real works

• Example sentences from Japanese novels & web fiction (Massif)
• Hear “食べてすぐ寝ると牛になる” pronounced in real videos (YouGlish)