YOU SAID:

peppa chan what are you doing in my bento

INTO JAPANESE

ペッパちゃん、私のお弁当で何してるの

BACK INTO ENGLISH

Peppa, what are you doing with my lunch

INTO JAPANESE

ペッパ、私のランチで何をしているの

BACK INTO ENGLISH

Peppa, what are you doing at my lunch

INTO JAPANESE

ペッパ、私の昼食で何をしているの

BACK INTO ENGLISH

Peppa, what are you doing at my lunch