YOU SAID:

I have substantiel testicles

INTO JAPANESE

私は実質的な睾丸を持っています

BACK INTO ENGLISH

I have a substantial testicle

INTO JAPANESE

私はかなりの睾丸を持っています

BACK INTO ENGLISH

I have quite a few testicles

INTO JAPANESE

私はかなりの数の睾丸を持っています

BACK INTO ENGLISH

I have quite a few testicles