Language:
كتاب النكاح
67  
Wedlock, Marriage (Nikaah)
(119)
Chapter: A woman should not look at or touch the body of another woman to describe to her husband
(118)
باب لاَ تُبَاشِرُ الْمَرْأَةُ الْمَرْأَةَ فَتَنْعَتَهَا لِزَوْجِهَا
Sahih al-Bukhari 5241

Narrated `Abdullah:

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."

حَدَّثَنَا عُمَرُ بْنُ حَفْصِ بْنِ غِيَاثٍ، حَدَّثَنَا أَبِي، حَدَّثَنَا الأَعْمَشُ، قَالَ حَدَّثَنِي شَقِيقٌ، قَالَ سَمِعْتُ عَبْدَ اللَّهِ، قَالَ قَالَ النَّبِيُّ صلى الله عليه وسلم ‏ "‏ لاَ تُبَاشِرِ الْمَرْأَةُ الْمَرْأَةَ فَتَنْعَتَهَا لِزَوْجِهَا كَأَنَّهُ يَنْظُرُ إِلَيْهَا ‏"‏‏.‏
Reference : Sahih al-Bukhari 5241
In-book reference : Book 67, Hadith 174
USC-MSA web (English) reference : Vol. 7, Book 62, Hadith 168
  (deprecated numbering scheme)