I use velvets alot in my quilts...can't seem to "conform" to the cottons and calicos and such...if it is washable or not, since most of my quilts have silks and velvets in them and would prefer dry cleaning anyway.
I would attach pics but can't seem to get them in here but, of the only two quilts I have completed, both used velvets, silks and taffeta...the stretchy stuff is tricky but, good pinning or a fusible interfacing stabilize everything very nicely and the really thin interfacing doesn't effect the "hand" of the fabric at all.