Sahih al-Bukhari Book 67, Hadith 173
The Prophet (ﷺ) said, "A woman should not look at or touch another woman to describe her to her
husband in such a way as if he was actually looking at her."
My foster uncle came and asked permission (to enter) but I refused to admit him till I asked Allah's Apostle about that. He said, "He is your uncle, so allow him to come in." I said, "O Allah's Messenger (ﷺ)! I have been suckled by a woman and not by a man." Allah's Messenger (ﷺ) said, "He is your uncle, so let him enter upon you." And that happened after the order of Al-Hijab (compulsory veiling) was revealed. All things which become unlawful because of blood relations are unlawful because of the corresponding foster suckling relations.
The Prophet (ﷺ) said, "A woman should not look at or touch another woman to describe her to her husband in such a way as if he was actually looking at her."