Sufyan (may Allah have mercy on him) and Abu Ishaq (may Allah have mercy on him) say that Sayyiduna Ali (may Allah be pleased with him) said: Do not make up Ramadan in the ten days of Dhu al-Hijjah, do not fast on Friday alone, and do not have cupping done while you are fasting.
(Sayyiduna Ali (may Allah be pleased with him) disliked making up fasts in these ten days because he held that the make-up fasts should be consecutive. So when the obligatory make-up fasts are more than nine, their continuity would be broken by the Day of Sacrifice and the days of Tashriq.)
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8396