how about ask D whether she'd like to be with her mom that night. If so, use my suggestion plus "and D would really like to stay with you that night, so can we swap nights? I'll probably want to do the same on my b-day, too"
When the men on the chessboard Get up and tell you where to go; And you've just had some kind of mushroom And your mind is moving slow; Go ask Alice... I think she'll know.
