Mother and Kid

One summer evening during a violent thunderstorm a mother was tucking her son into bed. She was about to turn off the light when he asked with a tremor in his voice, "Mommy, will you sleep with me tonight?"
The mother smiled and gave him a reassuring hug. "I can't, dear," she said. "I have to sleep in Daddy's room."
A long silence was broken at last by his shaky little voice: "The big sissy."