If you start the Scourge of Winter mission on Venus, skip all the ads until you get to the final boss. Draskis is his name I believe. Make sure you have a rocket launcher and the three of coins. Before entering, use the three of coins. When you enter, shoot Draskis(with a primary or whatever) until he gets really low health and then walk up to him and shoot a rocket killing both him and you. This will count as killing an Ultra(which with the three of coins can drop an exotic) and also restart that check point since you died at the same time. Simply use a three of coins before entering each time and repeat the process. Now since the nerf on the three of coins, there are less drops but they do still drop. Fastest and easiest way to farm exotic engrams I've found.

And by "takes a few seconds", I mean takes a few seconds to kill him. Not a few seconds between exotic drops. Just to clarify