Pinched, like above, actually squeezing the shoulder blades together? Nope. But good old "standing up straight" and making sure the shoulders are pulled back slightly, not rounded forward? Yep.
You might feel a stronger contraction throughout the entire shoulder girdle (delts, upper back muscles, and traps together), but you "should" be able to feel an overall higher delt contraction by deactivating the surrounding musculature as much as possible, so that the delts themselves have to do all the work.
One way to help this is to think about reaching the dumbbell out to the side wall during the movement and at the peak contraction.
Considering this, plus what you listed as your weekly routine in your thread about Sarcev, you should consider temporarily reducing chest and shoulder work and increasing total back work. A rule of thumb for healthy shoulders is to have 1:1 or even 2:1 "pulling" to "pushing" (basically rows/pulldowns to chest and direct shoulder work).
As you mentioned in the other thread, you're training back once a week, chest once a week, and shoulders twice a week. That's basically one "pull" and three "push" sessions. An argument could probably be made that doing biceps twice a week might also be contributing (slightly) to further increased front delt activation that could be exacerbating the issue.
Decide what your over-riding priority is for now. If it's shoulder-health and addressing the posture issue, dropping one shoulder session and adding a second back session would be appropriate. If it's delt size, make the best of the situation and do what causes shoulder growth.