From my own experience, though, I think it might be easier to find someone who is more of a generic babysitter type to take care of your twins, which (IMO) would also let you do the 'fun stuff' with your DS.
Oh, I wish I could! But I have one extremely fussy baby that drives everyone, including me, insane and won't take a bottle. Which is not to say that she won't grow out of that over the course of the next year (hopefully!), but right now it makes finding a sitter for them so that I can work with DS pretty difficult.
