YOU SAID:

I really am about to pee my pants

INTO JAPANESE

私は本当に私のズボンをおしっこしようとしています

BACK INTO ENGLISH

I'm really going to pee on my pants

INTO JAPANESE

私は本当に私のズボンにおしっこをするつもりです

BACK INTO ENGLISH

I'm really going to pee on my pants