My Friends Tigger and Pooh

You Ain't Just Whistlin' Tigger (1x17)

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While out on a case, the Super Sleuths decide to split up and need a way to signal each other. Darby decides on whistling, which Tigger goes along with even though he can't whistle. When he finally admits his secret, Pooh and Darby agree to help him to learn. Tigger, however, quickly becomes frustrated when he can't master it right away.