This undated sketch courtesy of Quirk Books shows a diagram for the Underdog activity from "The Art of Roughhousing," by Anthony T. DeBenedet, M.D. and Lawrence J. Cohen, Ph.D. This book is a new ... more 
This undated sketch courtesy of Quirk Books shows a diagram for the Underdog activity from "The Art of Roughhousing," by Anthony T. DeBenedet, M.D. and Lawrence J. Cohen, Ph.D. This book is a new parenting guide to good old-fashioned horseplay. (AP Photo/Quirk Books) less 
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Associated Press | Photo By Quirk Books
Tue, Jun 14, 2011 11:03 AM EDT