YOU SAID:

i need his thicky dicky

INTO JAPANESE

私は彼の厚いディッキーが必要です

BACK INTO ENGLISH

i need his thick dick

INTO JAPANESE

私は彼の太いペニスが必要です

BACK INTO ENGLISH

i need his fat dick

INTO JAPANESE

私は彼の太ったペニスが必要です

BACK INTO ENGLISH

i need his fat dick