Can you describe the nightly Chavadi procession and its origins?

The Chavadi procession was a regular event where Sai Baba would sleep at the Chavadi on alternate nights, with the other nights spent in the Masjid. According to Chapter 37, this practice continued until His Samadhi. The formal celebration, including worship, bhajan, and adoration of Sai in the Chavadi, began on December 10th, 1910. On the designated night, a bhajan group would gather at the Masjid and perform devotional songs in the pavilion until midnight, creating a spiritually charged atmosphere for Baba and the devotees before the procession would commence.