[jiggy2011]

Please, enlighten us.

[bradleyland]

When you try to put a hand/elbow/knee down on the mattress, there's a good chance you'll slip in to one of the slits in the mattress.

[freehunter]

Although the leverage you could get by digging your feet in would be crazy. Silk sheets feel nice but are wicked slippery.

[andrewingram]

Good thinking!

[philwelch]

On the other hand, you can stick your feet into the slits for better leverage.