Also, winter is rough and we want to keep our Alocasia living. What does it mean to "whack off the tops leaving a bit of stim"? Do we wait till the elephant plant's leaves wilt and die? It is still very lively and just produced a new leaf since bringing it inside. What should we do for the winter?

Water stored in the stem of the plant which is correctly the plant's base or axis and not the petiole that supports any leaf blade is "leaking" through the leaf blade since it doesn't have any other way to escape.

When the plant was in the ground the water collected by the roots was stored in the stem and then drawn up the petiole to the leaf blade. The water was "pulled" by evaporation through the leaf lamina into the atmosphere. The water isn't pushed up but instead is drawn up by the hydraulic force created by evaporation.

Since the plant has been uprooted it is filled with water and there is no longer natural evaporation in process. The water must escape somehow and simply "leaks" through the leaf blades. This is quite common in aroids and other plant species.

Chopping off the leaves means to totally remove them. It is best to cut off the petiole as well. The petiole is the part most people incorrectly call the "stem".