I've explained it a few times on here. But yeah it's the best way to reheat leftover spaghetti. You take some olive oil and put it in a frying pan, a little more than enough to cover the whole bottom of the pan is a good amount, you don't want to use too much. Then you throw the spaghetti in, chop the meatballs in 1/4s, and cook it over medium stirring here and there until the spaghetti and meatballs are hot again. Make sure to have some bread to soak up whats left on the plate aftewards too, it's amazing lol.
From what I've been told it's an old school Italian way to prepare leftovers.