Musnad Ahmad 26:856

Muhammad ibn Ja'far narrated to us, Shu'bah narrated to us, from Sulayman, he said: I heard Abu Wa'il narrating from Abdullah, from the Prophet, peace and blessings of Allah be upon him, who said: "If you are three, then two must not whisper to each other excluding their companion, for that would sadden him. And a woman must not touch another woman, then describe her to her husband, as if he were looking at her."