First AG, false bottom question

I had a great weekend, brewed the O'dark :30 clone from BYO magazine. Its a cascadian dark ale. The grain bill was around 12 lbs. I used 3.7 gallons of strike water. It was my first all grain. O used a 15g sanke MT w/ false bottom. The grain was able to creep under the false bottom and cause a stuck sparge. I am wondering how people keep their FB from rising when they are mashing. It was my first AG and so I was very eager to mix out all the dough balls. I was using a wood mash paddle to stir the mash. I bumped the bottom and that may have been what caused the fb to raise.

u can use a stainless hose clamp on your dip tube to keep pressure on it.

I personally don't use a FB, but my brewing buddy does. He bought some 1/4" silicone tubing, cut a slit in it, and put it around the diameter of the FB. It creates a perfect seal and keeps the FB in place.