Shibaraku : for a time being

Watanuki accidentally calling Yuuko ‘mom’

The cape, of course, was originally Clow's, but there's no way Watanuki would know that. I have a theory that Yuuko could have been his actual mother in a pre-loop timeline, but since he has no memories of her this way and it would be presumptuous to simply take over that role, she makes a great "cool aunt," and that's the position she sticks to in Watanuki's life.