She actually tickles Jack.
I was hoping beyond hope that WILL would be the one who was tickled, but in the original airing of the show last season on NBC, Demi Moore tickles Jack (Sean hayes). Jack hires Demi to be his babysitter, like she was when he was a kid. Apparently, they used to play a game where Demi used to tickle Jack (something about Mr. Tickle Wickle) and she tickled him til he laughed like crazy. Haven't you noticed how much tickling is cut of out sitcoms when they are re-aired on TV?? I wonder why that is?!?!