I used to know how to do this, but that was some time ago, and it's a blur now.
As I recall, it used to be possible, somehow, to offer an intended affiliate or group of affils. a coupon code exclusive to them (for example, based on their site name, fb group name, their specific brand, etc.) which they could, in turn, give away to their customer base online.
This code, which I could generate, but have forgotten how, would usually be in the form of intelligible letters, not garbled nonsense, and would be a real phrase. For example, TWENTYOFF, if the intention was to allow the affiliate to offer 20% off the regular price of my product to their customers. Or, if the intention was to really make it exclusive to that affiliate, then the code could read FRANKSDISCOUNT, assuming the guy's name to be Frank, of course.
Does anyone know of a working method or plugin that could create these types of coupons to help me with my promotions? Many thanks for any help with this.