This is my rather sad attempt at a welt pocket. Which, frankly, looks awful and won't lie flat at all. Especially in the corners. Since I already cut the slash, I'm not sure how to salvage this. I could maybe widen the seam allowance and make the welts more narrow, but it may be too late.
Needless to say, this is why welt pockets are on my check the technique list. I've never managed a good one yet.