Sayyiduna Abu Lubabah bin Abd al-Mundhir al-Ansari (may Allah be pleased with him) narrates that on Friday the Messenger of Allah (peace and blessings be upon him) supplicated for rain and said: 'Allahummasqina, Allahummasqina' (O Allah, give us rain; O Allah, give us rain). Abu Lubabah (may Allah be pleased with him) stood up and said: O Messenger of Allah (peace and blessings be upon him), the dates are lying in the drying yards, and we do not see a single cloud in the sky. The Messenger of Allah (peace and blessings be upon him) said: "O Allah, give us rain to such an extent that Abu Lubabah stands naked and blocks the drain-hole of his drying yard with his waist-wrap." The narrator says: The sky became overcast and it rained, and the Messenger of Allah (peace and blessings be upon him) led us in prayer. The narrator says: The Ansar went to Abu Lubabah (may Allah be pleased with him) and said: O Abu Lubabah, by Allah, the sky will not clear until you stand naked and block the drain-hole of your yard with your garment, just as he (peace and blessings be upon him) said. So Abu Lubabah (may Allah be pleased with him) stood naked and blocked the drain-hole of the yard with his garment, and the sky cleared.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب صلاة الاستسقاء / 6435