I had a question in the season 2 intros they show Wendy getting kissed by potsie and she throws ice cream at his shirt. I'm curious what episode was that on or was it never in an episode? Any help would be appreciated.

I had a question in the season 2 intros they show Wendy getting kissed by potsie and she throws ice cream at his shirt. I'm curious what episode was that on or was it never in an episode? Any help would be appreciated.
A lot of clips you see in the opening sequence weren't from an episode though some of them are. And this happens to be one of the clips that's never been shown in an episode.