YOU SAID:

I really want to let loose and pee in my pants.

INTO JAPANESE

本当は脱がしてパンツの中におしっこしたい。

BACK INTO ENGLISH

I really want to take it off and pee in my pants.

INTO JAPANESE

どうしても脱いでパンツの中でおしっこしたい。

BACK INTO ENGLISH

I really want to take it off and pee in my pants.