So you wake up at 7 am on a Sunday morning because you can hear your not-quite-yet-2-year old laughing in his bed as he practices all the words he knows (>10/language now). Since you went to sleep at midnight after watching stupid crappy X-files movie and reading old science papers related to your hot research, you think "he's happy and laughing, I'll just sleep a little more".
This a dangerous dangerous thought process. It will lead you to sleep for another 20 minutes and wake up well rested. You will hear you not-yet-2-year-old still happily laughing and playing in his crib. You can also hear the crib creaking and some jumping going on, and since you know your young child is able to climb out of the crib you'll go to get him. You'll walk toward his door, smiling to yourself about the wonderful day you're about to have, since he's woken up happy and you're well rested.
He hears your footsteps and gets very excited as he realizes you're coming to get him. This makes you very happy. Thinking all is well, you open the door to his room, he comes running to the end of the crib, arms reaching out. My gosh you think I"m getting a big hug first thing, what a great morning. You turn on the light and you see your monkey, arms reaching out as far as they can over the side of the crib. You walk in to get that hug.
And you get a diaper handed to your with a sweet "ank you" instead.
Oh and he peed on the bed.
The lesson? Perhaps it not a good idea to let you child play in his crib, if he can remove his diaper.
4 hours ago