I think the actual feeding part is done fairly discreetly, however to latch DD on I currently whip out my entire boob, faff with DD's positioning a bit, and then faff with latching on. When she's done she tends to whip herself off, again leaving me exposed - it then takes me a good minute of faffing before I can do up the stupid clip on my cup again.
I refuse to buy one of those daft breastfeeding apron things, and I'm not overly keen on draping things over DDs head - if nothing else I need to see what I am doing,