YOU SAID:

and that's when he knew he had pumped his pants

INTO JAPANESE

その時、彼はズボンをパンプしたことに気づきました

BACK INTO ENGLISH

That's when he realized he pumped his pants

INTO JAPANESE

その時、彼は自分がズボンを上げたことに気づきました

BACK INTO ENGLISH

That's when he realized he had pulled up his trousers.

INTO JAPANESE

その時、彼はズボンを引っ張ったことに気づきました。

BACK INTO ENGLISH

That's when he realized he had pulled his pants.

INTO JAPANESE

その時、彼はズボンを引っ張ったことに気づきました。

BACK INTO ENGLISH

That's when he realized he had pulled his pants.