I have just finished a muslin of a pair of pants. The legs hand nicely and without the crease mentioned in the title the pants above the leg fit well insofar as comfort and ease.

The problem is that there is a diagonal crease which runs from the crotch curve to 2″ in from the side seam and 2″ below the waist. (Basically it ends at the bulge in my high hip.) At the center of the crease, the fold is about 1/2″ (or 1″ total) tapering to nothing at each end. It looks really ugly.

What kind of adjustment do I make to remove this diagonal crease and restore the fitting ease in the back?

Any ideas? Many thanks