I figured I'd give Megan a break and take this one on.
I'm not really sure what Margo's getting at in the second panel. Like, is she implying that Doris has to ask multiple times after their initial agreement, or else it's nullified? "Just checking again, guys, are you still planning on being my bridesmaids?!" So if she doesn't ask again, they're off the hook? Or is she planning to misbehave so much as Doris's bridesmaid that no one else will ever ask her again, and this makes the whole humiliating process worthwhile? I just REALLY hope Doris puts them in some awful taffeta number and the whole wedding goes down with Lu Ann crying over how bad it looks with her brunette hair, and with Margo undertaking some kind of Carrie-like revenge. "That's the last time a man dares to innocently flirt with me and then allow his mousey fiancee to ask me to be a bridesmaid! They're all gonna laugh at YOU, Jack."