It finally arrived today. Here's a picture of the package nestling next to the flowers.
And when it opened, I found this.
I rang up the Guy to say they had made a mistake and sent a blank mug without including a message. He seemed strangely complacent.
Then he let me in on the secret. "Pour something hot into it."
Oooh, magic! I heated some water and poured it in. And there it was.
If you can't read it, the words say, "Here I am, right next to you."
I can't express my feelings better than to refer Banno's words: "Hope it is so nice that it does take you by surprise, even though you are expecting it."