Honey the main thing about stretch material is to NOT stretch it when doing that design.Now take a deep breath. Best thing is first look if your design is very stitch intensive. That can be a problem too. But the best way is to NOT hoop . Just use sticky or the sticky spray and then the basting is best. Wish we could all be there to help . It would be fun anyway. Hee! Hang in there. It will be worth the effort in the end. You will be the "queen of all' when someone gets that special gift.

I actually use a backing paper that sticks on. You peel away paper and it sticks.
Have done many T-shirts and never a problem.
Good luck

Bethelb gave you good advise. Me myself always use sticky tear-away stabilizer , I put that on the hoop with the sticky site above , so you can lay down the shirt on the sticky material, and it cannot stretch anymore.it's fixed on the sticky tear away stabilizer.But my first t-shirt ( when I didn't know this were a mess too. So don't panic just try this.

I haven't done a t-shirt yet so this is good advice for anyone doing it for the first time Thanks for asking and thanks for the answers

look for the tutorial on tshirts at the embroidery library, they sometimes have free videos

Marthe I use an iron fusible mesh to do tshirts and have no problems. As someone has already said it may b in the design itself. Some designs are just too dense for t shirt material. Better luck next time *

The denser the design, the more stabilizer you need. I use a temporary adhesive to affix my OESD poly mesh stabilizer. I then hoop both. Then, I ALWAYS affix with straight pins some water soluable stabilizer on top of the design area, so that my stitches don't sink into the t-shirt material. IF the design is very dense, I will float a piece of tear away underneath. I do dozens of shirts weekly and this is how I do them.;)

There are many methods as you see here. Try these ideas, you will find what works best for you. I use the mesh, but never hoop, because you will still get some stretch. See the advice in a previous post, and check out the info from Floriani, it works no matter what brand of stabilizer you use. Also on the site, under solutions, there is a downloadable pdf file with recommendations on stabilizing all kinds of fabrics. Remember when hooping sticky stabilizer, hoop it with the paper on, then remove only the paper inside the hoop. To do this scratch an X from corner to corner with a pin and then around the inside of the hoop, and peel up the pieces. Then there is nothing sticking to the hoop.