Here's a quick three-exercise shoulder finisher to use at the end of upper body workouts when you're looking to really finish off your shoulders, particularly the posterior delts.
The three exercises are reverse flyes, external rotations, and face pulls, done in that order. They're ordered from hardest to easiest and are done in succession as a mechanical drop-set, so don't rest in between exercises.
Do 6-10 reps of each exercise, 1-2 drop sets. While this is a high-rep finisher, it's still important to keep good form and do each rep deliberately as opposed to just pumping them out. Trust me, you'll still get a huge pump.