Slept like a baby. Okay - this saying now confuses me. I always thought it meant that you slept really well. Now that I have 3 babies it has a new meaning. The following is what I have come to understand this saying to mean.
Wake every 3 hours hungry.
Often poop and/or pee in your pants while sleeping.
Fart so loud it wakes you up and makes you cry.
Arms flail waking you up and making you cry.
Slept wrapped up like a mummy.
Chewed on a piece of rubber to make yourself fall asleep.
Slept while someone held you.
Slept on a mattress with no pillows.