I think it might depend on the LO. He may well be finished though and won't ever ask again.
On the other hand, if he does ask again (perhaps if he's feeling unwell/scared/sad or just needing comfort) but you'd like him to be finished (and chocolate and lasagne and milk in tea do sound like very good reasons for that!

), you could perhaps tell him that your milk has run out now and offer him an alternative drink and a cuddle if he wants one.