Musnad Ahmad 931:4

Isma'il narrated to us, from Yunus, from al-Hasan, from Ubayy: That a man expressed himself with the expression of the Jahiliyyah (pre-Islamic ignorance). He mentioned the hadith, and my father (Ubayy) said: We were commanded: "If a man expresses himself with the expression of the Jahiliyyah, then bite him with his father's private part, and do not use euphemisms."