More often than not, 
if there is a small child in the wedding party, they’re going to be rather shy around the photographer. Frequently, I can turn this into a game of hide-and-seek, or a kind of peek-a-boo, but with a camera. I often find that my best shots during these games are taken when shooting from the hip, as it were. I find that the kids respond better over time when I don’t constantly have the camera in front of my face. If they can see my eyes and my smile, they start to realize that that guy in black with all the hair on his face (I have a beard) isn’t so bad after all. I do this by holding the camera out away from me, pulling on the camera strap for tension, and guessing the framing of the image. I’m pretty good at it. After a bit of this, the kids almost universally warm up to me and start seeing me as a friend. By the reception, they are practically hogging the camera, finding ways to position themselves in front of me on the dance floor or tugging on my sleeve to say “Mister! Take my picture!”
Apparently, this only works temporarily as evidenced by my own kids who will do just about anything to vacate the area when they see Daddy coming at them with the camera. Oh well. For them, I’ve found that ice cream is a pretty good bribe.