Sewing a pleat into a bedspread

Hi, I came across these forums while doing some searching, and this is my first post. Can anyone help me with a sewing idea I have?

I have purchased fabric to make a bedspread for a king size bed (gold). Although it is going to be a throw bedspread, I was thinking of putting pleats in a contrasting color (red) at the two corners of the foot of the bed. I imagine a design where the red interior pleat would just barely peek out from the gold.

I'm thinking that the red part would be cone shaped and set in somehow to the top fabric. Is this one of those times when you take practice fabric and fiddle with it until it works? Or are there any instructions out there for doing something like this?

Thanks!