Can you whip cottage cheese and use it as a icing?

Cottage cheese? NO. Cream cheese? YES. Warming the cream cheese will make it spreadable. Cottage cheese is curds and whey, lumps and liquid, and does not "melt" as such so you need a binder to use it, something like egg whites whipped in MIGHT work. Whipping will break up the lumps and the hipped egg whites will add stiffness. Press the cottage cheese first to get out as much liquid as you can. If it is too thick after pressing, you can add a little liquid back while you run the mixer. I've used cream cheese before, with grape jelly "folded" in to the warmed cream cheese so it makes streaks. I have never tried cottage cheese.