This is a variation of the traditional Cuban press where you stand with a barbell, do an upright row, and then go into external rotation before pressing overhead.
With the lying dumbbell version, you eliminate the upright row and initiate the movement with what looks a bit more like a face pull. Use very light weights as you're training patterning, the very small muscles of the cuff and, to a lesser degree, the lower traps.
Go into retraction and do a face pull. From there, externally rotate and press. To get the lower traps more engaged, try to raise the dumbbells up as you do the pressing motion. Bring the press back, go into internal rotation, and back to protraction. Do 8-10 reps for 3-4 sets.