Tonks wasn't ignoring Dean. Not completely, anyway. She was, however, trying to get the other woman's spirits back up. "Don't have chocolate." Muttered to the man. So this would have to do.
"What was that, Luna? Didn't hear ya right." An impish smile appeared, as she was watching Luna, and an ear perked. A rabbit's ear. There was a set of rabbit's ears popping right up from the moptop of pink. Well, actually, they less popped up and more just appeared. Like they were always there. Luna was the young woman who, at fourteen, faced down Death Eaters. So Tonks wasn't treating her like a child, but rather getting the blonde to a spot where she could function without being crippled by her fear. Laughter helped with that.