I talk about this technique a lot in my classes. Sharon Shamber has a great little trick for getting that fabric to do what you want it to do. I had the great pleasure to take a workshop with her years ago and she is a wealth of great information. This is one of the best things I got out my time with her that day. She’s got her own you-tube channel with lots of great info as well as two websites. http://purpledaisiesquilting.com/ and http://sharonschamber.com/
Here’s a great link on blocking your quilt
https://www.youtube.com/watch?v=iQnHLkA7bTs
And here’s how to square up that wonky block without having to trim off any points. It a 2-part video. Here’s part 1.
https://www.youtube.com/watch?v=i6aplw_tVZc
and here’s part 2.
https://www.youtube.com/watch?v=lIjZqABo2NY
Don’t you just love YouTube!