The rishi Narada came to Ayodhya one day, shortly after Rama's coronation. He saluted Rama and Sita in the throne room, and then he noticed that Hanuman was there.
"O Hanuman!" said Narada, "Sita wears a vermilion dot on her forehead to honor Rama. How do you honor him?"
Hanuman rushed to the marketplace and bought all the sacks of vermilion that were for sale. He returned to the palace, emptied the sacks in a heap on the floor, and rolled in the powder until he was covered all over.
"I honor him this way," Hanuman said, beaming with pleasure.
Inspired by: Sita: An Illustrated Retelling of the Ramayana by Devdutt Pattanaik.
Notes: This story is on p. 269 of the book. In Lutgendorf's Hanuman book (story 26; p. 157), Sita tells Hanuman that she wears the vermilion dot to extend Rama's life, so Hanuman rushes to the marketplace and rolls in the vermilion.