if you want the pleats neat and even, you either:

A: Lie it down and pleat, then lie down on the pleats, then wrap and belt.
B: Lie it down and pleat, iron the pleats down really well, and stitch them in place.

If you don't care about neat pleats, then standing and doing it isn't too terribly tricky. Just requires practice, but it won't look neat and even.

As to being discrete, you should be wearing at least a mid-thigh shirt, so that usually takes care of that.