Sayyiduna Jabir bin Abdullah (may Allah be pleased with them both) narrates that water was sprinkled on the grave of the Prophet (peace and blessings be upon him), and the one who sprinkled the water on it was Sayyiduna Bilal bin Rabah (may Allah be pleased with him). He began with a water-skin from the head side, on the right side of the grave, until he reached the feet. Then he threw the water towards the wall, because he could not go around from the wall's side.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 6743