Language:
كتاب الاعتكاف
33  
Retiring to a Mosque for Remembrance of Allah (I'tikaf)
(2)
Chapter: A menstruating woman is permitted to comb the hair of a man in I'tikaf.
(2)
باب الْحَائِضُ تُرَجِّلُ رَأْسَ الْمُعْتَكِفَ
Sahih al-Bukhari 2028

Narrated `Aisha:

The Prophet (ﷺ) used to (put) bend his head (out) to me while he was in I`tikaf in the mosque during my monthly periods and I would comb and oil his hair.

حَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، حَدَّثَنَا يَحْيَى، عَنْ هِشَامٍ، قَالَ أَخْبَرَنِي أَبِي، عَنْ عَائِشَةَ ـ رضى الله عنها ـ قَالَتْ كَانَ النَّبِيُّ صلى الله عليه وسلم يُصْغِي إِلَىَّ رَأْسَهُ وَهْوَ مُجَاوِرٌ فِي الْمَسْجِدِ، فَأُرَجِّلُهُ وَأَنَا حَائِضٌ‏.‏
Reference : Sahih al-Bukhari 2028
In-book reference : Book 33, Hadith 4
USC-MSA web (English) reference : Vol. 3, Book 33, Hadith 245
  (deprecated numbering scheme)