Originally Posted by Prism99
You can "fan" the seams at the intersection. I don't know how to describe this; maybe someone else can. You put your finger in the center, then turn each seam clockwise (or counterclockwise) so they create a fan in the center. A drop of water and pressing keeps them this way.
It can also help to unpick the thread inside the seam allowance.
I went to a class on a hex block and the lady who made the pattern taught it. She had us work the center open with our finger until the center fanned out, just like you described. It worked pretty well.