Roaring like a lion

Blaine seems to be a sponge these days - we'll do something once or twice with him and he tries it and then does it on his own. One day, during our reading time, I said "What sound does a lion make?" and then made a somewhat meager, but identifiable, lion noise. I continued this for a day or so and then he just did it (and I will add here that his roar is a lot better than mine). The problem is that we've tried to capture this on video about 10 times and he either A. won't do it or B. walks away from us. Today though, we captured a lion noise... but it's not very good. He's not really giving it his all. Usually he makes a deep long growl... but not this time. I'll get it one of these days.