Sayyiduna Anas bin Malik (may Allah be pleased with him) said that the Prophet (peace and blessings be upon him) used to take his midday rest at the house of Umm Sulaym (may Allah be pleased with her). She would spread a leather mat for him (peace and blessings be upon him), collect his (peace and blessings be upon him) sweat and mix it into her perfume, and she would spread a small mat for him (peace and blessings be upon him), and he (peace and blessings be upon him) would pray on it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4198