YOU SAID:

i have a lemon for a mouth

INTO JAPANESE

私は口の中にレモンを持っています

BACK INTO ENGLISH

I have a lemon in my mouth

INTO JAPANESE

口の中にレモンが入ってる

BACK INTO ENGLISH

There is a lemon in my mouth

INTO JAPANESE

口の中にレモンがあります

BACK INTO ENGLISH

There is a lemon in my mouth