When they were babies, each of my kids had their own way of letting me know they were awake in the morning and ready to escape the confines of their cribs.
Precious Daughter used to slam her heels into the mattress.
Mighty B. would stand up, hold the side rail, and bounce on the mattress for all he was worth. I sincerely feared he'd flip himself over the rail onto the floor.
Her Nibs stands up, holds the side rail, and shimmies her butt back and forth to thump the side of the crib against the wall.
It's a wonder that crib hasn't collapsed from the abuse.