How do I get this off?

I got a helmet for Konrad a few months ago, and have tried on and off to get him to wear it. He's doing better with it, but he still can't forget that it's on his head...he's constantly trying to take it off. And that makes it hard to get a centered picture of him!

And Konrad's head is not as large as Lukas' was at this age (it's probably more of a normal size), so I couldn't find a helmet small enough for him. I got the toddler size, and it's still a little loose...but it fits Natalie perfectly! Now, if only she would keep it on...