Freezer paper is used extensively by quilters for a variety of purposes. I use it mostly for machine applique. Some people use it for paper piecing. It is also used for making compass stars (complex patterns that require accuracy).

Iron the shiny side of the freezer paper to the wrong side of your blocks. It peels off easily and should not interfere with your interfacing. I am assuming the interfacing was ironed to the t-shirt material, so the side that you would iron the freezer paper to should not have fusible on it.

Thanks for the tip on freezer paper... I am going to google that for ideas. But I am confused you said to iron the shiny side of the freezer paper to the wrong side of your blocks.... then you also said that the side that you would iron the freezer paper to should not have fusible on it...... my fusible interfacing is on the wrong side of my block (the back side) What am I misunderstanding???

How did you get your fusible interfacing to stick to your block??? I think the normal method is to iron the fusible to the t-shirt fabric, then cut your block. It is the fused interfacing that gives the t-shirt fabric stability. My understanding of interfacing is that it has fusible on one side. That is the side you iron to the fabric. Or did you use a two-sided fusible? I don't think two-sided fusibles are called interfacing, but maybe I am wrong about that.

Edit: I think I'm right about interfacing having fusible on only one side. Here is a Wikipedia article on it:
http://en.wikipedia.org/wiki/Interfacing