Ducky, I'm glad Lesley explained...that was exactly what I was going to suggest. Also,I am marking my background on the face of the fabric and then also marking the applique piece on the backside. I line up those markings and pin it in place so that it behaves nicely. Sounds like you need to give your piece a good quaking too...
On the tension adjustment issue...in the class that I took, she suggested a couple of things that are helpful. If you plan on doing LOTS of bobbin work- buy an extra bobbin..if you only do it occasionally- just use the one you have. Its easy to adjust- hold the tail of your thread in your right hand, hold the bobbin in your left hand below it. Drop the bobbin, it should drop about 1-2" freely, then stop. You should have to gently shake it with your right hand to make it drop again...this is "correct tension"..if it falls to the floor releasing a kabillion miles of thread...its too loose. If it doesn't move down at all...its too tight. :wink: I don't think you always need to adjust it..depends on what thread you are using... I can't remember whether she put the thread through the tension disc or not..(says the expert who has done this exactly 1 time- LOL!!)