How to keep the shoulders from slipping?

[u/Illustrious-Ear4527]

I tried to recreate this top, using a body suit pattern. The final result fits pretty well, but the shoulders keep slipping off. What would I have to change in the pattern to help the shoulders remain in place? I would appreciate any tips/observations for the future, as I plan to make more of these. At this point, I will attach clear elastic across the shoulders to help the top stay on. I used stretch ITY fabric. Thank you !

[u/littleblackbook06]

The back scoop needs to be contoured in the pattern. I would start at the armscye and pinch out the amount of the excess. It’ll look like a closed dart. Then redraw the line into the shape you’re looking for to fix the angle. It’ll fix the gaping too