YOU SAID:

my tail makes it impossible to sit

INTO JAPANESE

私のしっぽは、座ることを不可能にする

BACK INTO ENGLISH

My tail makes it impossible to sit

INTO JAPANESE

私のしっぽは座ることができない

BACK INTO ENGLISH

My tail can't sit.

INTO JAPANESE

私の尻尾は座れない。

BACK INTO ENGLISH

I can't sit on my tail.

INTO JAPANESE

しっぽに座れない。

BACK INTO ENGLISH

I can't sit on my tail.