I have always found that sleeping too much can be as debilitating as sleeping too little.
I do not think that sleeping is like eating. You can't "stock up" on it.
I believe, however, if you get weeks and weeks of really good sleep and take care of yourself you will be more resilient when the lack of sleep effects hit you than if you had not taken care of yourself. I suppose you can stock up on it that way.
There was a movie in which Charles Bronson and a Japanese actor are both in the old west. The Japanese actor plays a Samurai. He says, at some point, that he has learned how to sleep while walking. I always wondered if that were possible. I bet it is.
So you could probably sleep while doing a simple, repetative task.
