The Messenger of Allah ﷺ used to be cupped on the two veins at the sides of the neck and on the upper back between the shoulders. He would have cupping done on the seventeenth, nineteenth, and twenty-first of the month.
حدثنا عبد القدوس بن محمد حدثنا عمرو بن عاصم حدثنا همام وجرير بن حازم قالا حدثنا قتادة
كان رسول الله ﷺ يحتجم في الأخدعين والكاهل وكان يحتجم لسبع عشرة وتسع عشرة وإحدى وعشرين
Sourcing, its chain is daif. It was reported by Abu Dawud in the Book of Medicine, chapter on the location of cupping, no. 3860, and by Ibn Majah, no. 3483, from the hadith of Jareer bin Hazim through this route. Qatada narrated it using "an" (indicating a possible break in transmission).On this same topic, there is also a narration from Ibn Abbas [to come at no. 2053] and from Maqil bin Yasar [Ibn Adi 3/1148, and through his route Ibn Jawzi in al-Mawduat 3/214].