Well, I asked my
girlfriend last night about this whole
sexy underwear thing,
and she said that wearing
sexy underwear makes a
girl feel
sexy. Even if
the guy's never going to see a
stitch of it, it'll make her feel more
self-confident.
So chances are, if a
girl is out with you, and she wants to feel
sexy and
confident, than chances are pretty good that it's either a
date, or she wants
it to be one.
Of course she could just enjoy wearing nice
underpants all the time, and you're
just
barking up the wrong tree, but let's just pretend that she wants a
date.
Of course, as
rescdsk pointed out, by the time you see her
underpants, you're
pretty sure that she wanted a date, so I don't think there's any reliable way
to use
underpants quality as a sort of
early warning indicator for a
date.