Potter Puppet Pals is still the best.
The Marauders used to take turns taking care of Harry when the others had Order business or were too busy or needed a night off. It became a tradition among them, as they were passing the baby into the next caretaker’s hands, to say “you’re it. good luck.”
The last thing Sirius saw as he was falling through the veil was Remus running over to Harry, and the last thought that ran through his head was “you’re it. good luck.”