YOU SAID:

The narration is so boring that you smack your head with the heel of your hand to stay awake.

INTO JAPANESE

ナレーションはとても退屈なので、目を覚まし続けるために手のかかとで頭を叩きます。

BACK INTO ENGLISH

The narration is so boring that I hit my head with the heel of my hand to keep awake.

INTO JAPANESE

ナレーションはとても退屈なので、目を覚まし続けるために私の手のかかとで頭を打ちました。

BACK INTO ENGLISH

The narration is so boring that I hit my head with the heel of my hand to keep awake.