Am so good when am sleep check the correctness of this sentence?

The sentence meaning is very unclear. It could interpreted differently by every reader. Plus, it needs to be grammatically changed. Also, the sentence needs 'asleep' rather than 'sleep'.

For example:

I am so good when I am asleep.

The boy is so good when he is asleep.

It feels good to get a good night's sleep.

When I am asleep, dreaming is good.