Melissa: As far as the sticky dilator, I believe that maybe the problem is not suction, but might be lubrication drying/getting absorbed. This causes it to be like glue. The place where they often stick is near the opening, where the lube is exposed to air.
The slight twisting movement is possibly one way to solve it, as Rachel mentioned. I might also recommend keeping a small cup of water nearby for re-moistening as you dilate.
Any more troubles, call your doctor!!!
Hugs, Danielle