YOU SAID:

I gotta take a fat peepee

INTO JAPANESE

私は太った覗き屋に行かなければならない

BACK INTO ENGLISH

I have to go to the fat peeper.

INTO JAPANESE

デブ覗きに行かなきゃ。

BACK INTO ENGLISH

I have to go take a peek at Fatty.

INTO JAPANESE

デブを見に行かないと

BACK INTO ENGLISH

I need to go check on Fatty.

INTO JAPANESE

デブを調べに行かないと

BACK INTO ENGLISH

I need to go check on Fatty.