The video's been removed, I don't remember him tickling her in this scene (i'd love to see it again!), but I WILL say this:
This movie has some kind of tickling theme. In the beginning of the movie, Cher pokes/tickles either Susan Sarandon or Michelle Pfeiffer, later on a crazy lady (something like the mayor's wife) starts ranting and starts saying "tickle tickle tickle", and at another point in the movie, when the three actresses are cavorting in Nicholson's mansion he says something like "That's right ladies, let it tickle you". So, though I don't remember this scene (and I sure would love to see it!), it seems like a plausible thing, given the "tickling" theme throughout the movie (which, I must confess, I don't really get how it connects to the plot!).
Still waiting for the Michelle Pfeiffer scene from, I think it's called, "The Children Who Never Laughed", I've never seen that one either!