@malek is almost correct and then second comes @skumar83 and @Frederic Nuyttens
Only slight correction that dune bashing is not always you bash the dunes likes of Faya or big red, but traverse through the dunes means it can be slow or fast but through the dunes. Choosing tracks to drive in the middle of dunes is not dune bashing but offroading, that's the point I wanted to make here.
A lot of newbie joins on a drive with tons of offroad experience and get crested on the first dune they cross as either they been to track with other clubs or been to beach sand or roadside sand with inflated tires.
@desertdude correctly mentioned that desert safari guys stick to desert driving than dune bashing and just touch a couple of side slope to tilt the car and make tourist scream. Totally different world in that line of business when you have to please the tourist in 30 mins - 60 mins drive and make them jump on sunset point for selfies.