If double is Stayman, then I bid whatever I would do if RHO had passed to show this hand. If that involves bidding 2NT as a transfer to diamonds, then I bid that then 3NT, which hopefully should show a hand like this (a hand with long diamonds that wants to play 3NT). I'm not sure what I do now. If my 3D on the second round shows a game forcing hand, then I pass and await developments. I don't know whether or not to bid 4NT, 5D or to double 4C. Hopefully partner does.