This is an extended scene only featured in the German DVDs. It includes a longer version of the group eating dinner together and Ash giving a toast Link: corneey.com/qAYOJ3
I think Scott teased Cheryl because he wanted her more than the mundane Shelly, but he didn't know how to get her. And Cheryl's reaction means she don't ignored him too. It looks like flirting, and it's really a pity that this scene was cut.
Well, if we go by the TV Series, Cheryl and Chet may have had something going on... Of course, that character didn't exist at the time, so in the context of the scene as orignally written, you may be right.
