Cut your little boys' hair yourself. I've always done it myself so I have no idea how the professionals do it, because it is, indeed, a challenge. I go into the yard with my 2 1/2 year old, he gets a spray bottle, I have hair scissors (sharp) and a comb.
He gets to spray whatever he wants to, which he loves, and I, after spritzing the top of his hair with his squirt bottle, play crazy hair stylist, chasing and trimming whatever I can get up between two fingers, like the pros do. Go all directions, front to back, side to side for an even finished product.
Then, back inside the house, a half inch attachment on a set of clippers (buzzers) to finish the sides and back. If he gets upset about the clippers, try letting him have his hand on the clipper-handle with you and be sure he can see himself in the mirror. Then it's like he's doing it himself which is all a toddler wants out of life! He looks like a little man. So handsome! :)
TIP: Always err on the side of leaving it a little long. You can always play again tomorrow, but it takes weeks to grow back an over zealous mistake.
By Gail M from Burbank, CA
Original article and pictures take http://www.thriftyfun.com/Cutting-Your-Kids-Hair-2.html site