In the movie "Josie and the Pussycats" (not the most intellectually stimulating experience), there is one point where the girls are all being made up for their first big appearance. Must be about halfway through the film. Anyway, at one point the make-up brush tickles her neck and she has this really cute reaction - typical and spontaneous in that kind of situation. You can't hear any laughter, because there is music on at the time, but it is unmistakable. Only, don't blink too vigorously at the time, or you might miss it.