You then walk backwards down the cliff, supported by the rope, slowly lowering yourself down, enjoying the scenery en route. Most commercial abseils are belayed. If you were to just let go in panic, the trip leader could safely lower you down remotely, either from above or below. It's also quite likely that there'll be a decent section of overhang, so you get to spend some time just hanging out, admiring the view. Our Abseiling spot is next to the Blyde dam wall. Not for the faint of heart.
In case you have no idea what abseiling is all about, it's the art of lowering yourself safely down a rope. You wear a climbing harness, and are clipped onto the rope with some manner of descending device.