That is way too amatuerish you are not suppose to stop, specially going up hill and in too soft of sand. You always stop the vehicle at the top of the dune facing downhill. Always keep Gravity in mind, what goes up must come down. When in the desert Gravity is the big brother who get you out of all kinds of trouble.
One very important thing, always reinflate your tyres when back on the highway if you have deflated them for the desert.