Where's my Birthday?

Nicholas's birthday is coming up this weekend. I have a wrapped present to Nicholas from my mom in my closet. Nicholas spied it yesterday and you can imagine the excitement that his discovery brought. After a few minutes of Nicholas saying "When is my birthday?" over and over, with me answering "In seven days." every time, he became thoughtful. He looked up at me and said, "WHERE'S my birthday?" I paused to think about how to answer that one. While the wheels in my brain were turning Nicholas got an excited look on his face as if he had figured it out. He grabbed the front of his shirt, stretched it out in front of him and asked, "Is my birthday in my belly?"