Sayyiduna Abu Hurayrah (may Allah be pleased with him) said that the Prophet (peace and blessings be upon him) said about a man who had intercourse with his wife in Ramadan: "Free a slave." He said: I cannot find one. He (peace and blessings be upon him) said: "Fast two months." He said: I am not able to. He (peace and blessings be upon him) said: "Then feed sixty poor people."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8054