If your strong side knee isn't drawn up till it's tight and your weak or support arm elbow isn't directly under the gun then you will roll. Old saying is if it doesn't hurt the first time you ain't doing it right.
After awhile when your limber catches up to your position it will stop hurting, (mostly).
If you do it 2 or 3 or 4 times a week and get used to it you will stay limber, a couple months away from the tight position and it all goes south on you and you have to start over again.