It looks,like that would hurt worse than the back pain!
No it is really incredibly relaxing, though at first it can cause tenderness as it applies substantial pressure to areas if the body that are not used to receiving any pressure.
You are supposed to use it on the floor, but if you find that it applies more pressure than is desirable, you can also use it on a bed, which drastically reduces pressures applied.
But I found that after about three days of using it twice a day, I was able to completely lay on it without trying to lift myself off of it in any way.
And in order to be able to achieve sufficient enough pressure on the tailbone area for sciatica pain, I will put the roller under my butt in an area that is sufficiently meaty and life both my legs off the ground and hold them in the air such that the maximum amount of pressure I can achieve is placed on the tailbone.
Doing this makes sciatica pain just dissolve, which is great, because sciatica can hurt so bad at times it almost crippling.