What is your tent.
There are several varieties of silnylon out there, some more slippery than others.
Another issue is whether the tent pitches with the floor FULLY taut. If not, all the friction in the world inside the tent won't keep the floor from slipping and bunching up on the ground underneath.
I've had great luck with silnylon floors, but only taut ones, and only on level or almost level ground.
Among so-called self-inflating pads, the Nemo comes with the sil chevrons underneath, slips less than the Thermarest, packs smaller, and has more insulative value - see Roger Caffin's article on this site about pads. Tried a Thermarest this spring, and am going back to the Nemo.