sometimes if the quilt is very big and heavy the weight itself will keep it from moving around smoothly. if this is the case, you'll have to experiment with different maneuvers of body/quilt (such as holding the quilt over one shoulder) while you sew.

I cover my surface with a vinyl tablecloth and it lets the quilt slide around...
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ya'll are just wonderful - what great tips ... I will try them too I am learning how to stipple on my machine.

I have one of the teflon sheets and it does not help at all. Also, it makes changing the bobbin very difficult! Hope this helps.

Yes, the weight of the fabric causes what is known as "drag". They are a bit pricey, but if you can afford to buy a quilter's table where your machine is resessed below, making the throat plate flush with the table, that does alot to eliminate drag.