If you have a younger brother of nine or ten or thereabouts, you'll no doubt have to use some persuasion.
Most boys love dressing up and anyway we like to depart from everyday subjects for a change, don't we ?
I can always persuade Brian to pose as a soldier.
We made, between us, a paper hat some time ago for a play he was to take part in at school, so I suggested we'd use it for a drawing. He was soon as eager to make it interesting as I was.
He thought of the airgun, and the pose suggested itself. He stood on a chair for this pose.
Notice the proportions of the head in relation to those of the body. The head appears large doesn't it? and the shoulders smallish.
Often when children are reading or playing quietly, they strike nice poses and once they become interested, they'll usually keep still for a little while if you ask them. The first drawing took about 20 minutes and the second about 15 minutes.