Here's something simple that can relate to Christmas and the heart! You're going to love it:
Toe.
What do you do under the mistletoe and what time of year does it come? I'm so clever. You could pronounce it Toey or make it Toeby, but I think if you leave it as Toe, people will ask you why you named him that. Also when he gets big, you could call him Big Toe. Haha, I must stop myself before I use up all my wit for the day.Good luck.