Ive heard the saying "They want their cake and eat it too"
But, if it belongs to them, shouldn't they be able to eat it? I don't get it... :confused:

It means you want to be able to use something up but still have it. It would be like burning a wooden chair to stay warm but expecting to still have the chair to sit on afterward.

Have one's cake and eat it too - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Have_one's_cake_and_eat_it_too)