It's a very old trope, plenty of HRPGs have something similar, but usually it's a lot more basic and less elaborate than this game or KP.
I'm no porn-game archivist or anything, but I'd say that KP was the first game to properly do a waitress minigame (Clothing damage, please meters, different client orders, etc) every other iteration of it I had seen before that was pretty basic.
People have always wanted to fuck a waitress, so finding the first game to implement something of the sort would likely send you back to the early 2000s.