How it works on Erg Chebbi
A sandboard is a wooden or laminate board with foot straps and a waxed base. You walk up a dune face, strap in or sit down, and slide. The sand on the lee side of a dune is soft and steep, which is exactly what you want.
Speeds are modest — this is not snowboarding. The reward is the setting: you are sliding down a 100-metre face with nothing in any direction but more sand.