ENOfficial
Bukhari said without a complete isnad that Ibn ‘Umar used to have himself cupped whan he was fasting. Then he abandoned it and had himself cupped at night.
Source: sunnah.com
Other translations
Arabic
وَعَنِ الْبُخَارِيِّ تَعْلِيقًا قَالَ: كَانَ ابْنُ عُمَرَ يَحْتَجِمُ وَهُوَ صَائِمٌ ثُمَّ تَرَكَهُ فَكَانَ يَحْتَجِمُ بِاللَّيْلِ
sunnah.com