A type of tickling that involves two people: the giver and the receiver. The giver holds out both of his/her hands, in the way you would when you pick out berries from the trees, near the receiver's waists and tickle them (in a squeezing-the-berry kind of way) typically when they are unaware. In a sense, you are giving them a healthy berry of laughter. You usually tickle them until they don't want to have anymore chuckleberries.
Lucas gave Trixie a chuckleberry to cheer her up when she was depressed after her midterm.