I was watching this show and I have a couple of questions:

1) does this technique apply only to curved seams that have to stay flat (as for the skirt) or also to curved seams that do not have to lay flat (Ann's previous posts probably answered my question – but I'm asking anyway )

2) in the show Sandra says that if you want to topstitch, then you press the seam open. But what if you don't want to topstitch? Do you press the seam up or down?
In the written "tip" you read to press away from the curve but I don't understand. Away from the out-curve or away from the in-curve?

I've never sewn curves this way, but I can see how using the stay tape would work so much better than staystitching.
Luckily I'm working on a dress with princess seams and I'll try it