YOU SAID:

my uncle said he has to pee so he went out of the room and peed in his pants until he found a toilet in which he pooped

INTO JAPANESE

私の叔父は、彼がうんちをするトイレを見つけるまで、彼は部屋の外に出てズボンの中でおしっこをしたので、彼はおしっこをしなければならないと言いました

BACK INTO ENGLISH

My uncle said he had to pee because he went out of the room and peed in his pants until he found the toilet to poop

INTO JAPANESE

私の叔父は、彼がうんちするトイレを見つけるまで、彼は部屋から出てズボンの中でおしっこをしたので、彼はおしっこをしなければならなかったと言いました

BACK INTO ENGLISH

My uncle said he had to pee because he got out of the room and peed in his pants until he found the toilet to poo

INTO JAPANESE

私の叔父は、彼がうんちするトイレを見つけるまで、彼は部屋から出てズボンの中でおしっこをしたので、おしっこをしなければならなかったと言いました

BACK INTO ENGLISH

My uncle said he had to pee because he got out of the room and peed in his pants until he found the toilet to poo