its like those accodian handheld fans. with the end of it in your armpit and one side attached to the dress and the other to the sleeve so when the arm goes up, the fan opens
When I first heard your description I thought of something like this which I would consider a pleated kaftan, but I don't know if this is what you meant -Click-
Has anyone tried using a girth extender over an extended period of time instead of buying a new girth? Would that even work? I dont wanna buy a whole new girth but if there's some kind of drawback to extenders obviously I would have to.