means:The sound of a beating heart.

　　　心臓が動く音。

　　　 → DokiDoki suru.

　　　　どきどきする。

When nervous...For example, when you're watching a scary movie.When you are with someone you like.

Normal times...When you want to express the sound of heart movement.

explanation of symptoms...When telling a doctor that you have palpitation.

→The heart is pounding.

　胸がどきどきする。

Tips

+ ドキがムネムネする(Doki ga munemune suru)...very casual "胸がどきどきする".

+ Strong DokiDoki...ドッドッドッドッ（do! do! do! do! /not English "do".)

+The calm beat is sometimes described as "TokuToku(とくとく)".

type:sound