Loose sand and rear wheel drive don't really mix.
I got stuck on very wet long grass in a boggy field a while ago in my Sdrive. Wheels just spun and the DTC kept reducing the power.
Turned the DTC off (in fact I turned DSC off too) and floored the gas pedal. I was surprised at how well the car moved and how controllable it was. Rear wheels were still spinning, but I got out the field. Tyres were the ones supplied with car... RFT 225/45 Pirelli.
I'm not brave enough to take my Sdrive on sand
J.