be tickled pink

To be very pleased with someone or something. My family loves my fiancé as much as I do, so they were just tickled pink to hear that we're getting married. Your mother is really tickled pink that you've decided to go to her alma mater.

To be extremely pleased; to be overcome with amusement or delight. Both versions rest on the fact that tickling causes laughing, an expression of pleasure. The older is to be tickled to death, which dates from about 1800. Paulding used it in his play The Bucktails (1815, 4.2): “Stab me, but do not tickle me to death in sport.” Tickling someone pink means they turn pink with the blush of either pleasure or suppressed laughter. P. G. Wodehouse wrote (Nothing Serious, 1950), “Your view, then, is that he is tickled pink to be freed from his obligations?” Both expressions have largely supplanted to tickle one’s fancy, meaning to divert or please or amuse and in use since the eighteenth century. John Doran had it in The History of Court Fools (1858): “The joke . . . tickled the fancy of the Tirynthians.”