I used iron on cheapest I could find to stabilise my tshirts and i left mine on. The advice i was given was to pull the shirts to see which way they stretch then do the same with the fusible then iron it on so the stretch is in opposite directions as it will help your tshirts stay in shape and not stretch when sewing. Hope this helps as I am not good at explaining especially when I am in a hurry to go to work! Good luck!