Leave It to Beaver - Season 1 Episode 5 -

The Cleavers have new neighbors, the Donaldsons, and June sends Beaver over to welcome them with a vase of flowers. However, when Mrs. Donaldson thanks Beaver by kissing him on the cheek, Beaver becomes convinced that Mr. Donaldson will kill him because he let a married woman kiss him, and it's all thanks to Eddie Haskell, who planted that idea in Beaver's mind.