Wee One has a pretty regular bedtime routine, and it revolves around the letter B. Bedtime britches (an overnight diaper), bottle, brush teeth, book, and then bed. After the book and before bed is a prayer and song, but those don’t start with B, so I don’t include them. They’re part of the “bed” part of the routine.
I cradle her in my arms and rock and sing her “Baby Mine” from Dumbo, which I have done since she was about 4 months old, and Cohiba, who does not sing at all, has learned the words from hearing me sing it so many times.