YOU SAID:

the cat is on the self

INTO JAPANESE

猫は自分の上にいる

BACK INTO ENGLISH

Cats are on top of themselves.

INTO JAPANESE

猫は自分の上にいる。

BACK INTO ENGLISH

The cat is on top of himself.

INTO JAPANESE

その猫は自分の上にいる。

BACK INTO ENGLISH

The cat is on top of himself.