Doris, It is always a good idea to afix your quilt back to something before basting. Your batting and top can remain free, but the backing needs to be anchored to prevent your puffing problem. I use a cutting table, but before the cutting table used my glass topped dining room table. I got a set of binder from the office supply store. Be sure to get ones large enough to clamp to the table. Smooth out your quilt back face down on the table, centering the back on the table, and attach the binder clips. next lay center of batting, then the quilt top face up. Begining at the middle start your basting or pinning. When you are out of table, undo the binder clips and move to another section. This may seem quite tedious, but definately worth the trouble. One last tip, your quilt back should be larger than the top by approx. 2" all the way around, more is better.
Let me know if this solves your problem, and if there is anything else we can help you with.