Best way towards making someones cum taste better is having them be healthy and enjoy healthier food overall, from personal experience I know for a fact that any fried food will make your cum taste bitter due to the oil from the frying (gotta say my old submissive did say she preferred me not have any fried food after a visit we had over my grandparents for holidays and that was the main theme of the food we had). But since I do not want to post a huge wall of text, here's one website that I've found just in few minutes of googling, and it does capture most of my personal experience towards it.
Drinking cum should be about being degraded and feeling used and dirty, if you don't like the way cum taste don't drink it, this is kind of a silly post.......