When sewing on terry or any fabric with loops and nap, generally a topping stabilizer is used. These can be helpful, but have a limitation: They do not hold down the nap past the actual stitch, which means outlines can be lost in the surrounding fabric. Using the menu Utility->Add Knockdown Stitches you can create a gloabal underlay for the entire design. The underlay extends a few millimeters past the edge of the design, which helps the overall effect.