I'm thinking that by the time the day/fic is done, Snape might have more than one unpleasat memory concerning Sirius seeing his underwear!

Plus Tonks revealing she is the only dairy-free Metamorphmagus in existance, could be a great romantic moment for her and our wheat-free werewolf.

Shame they won't get a chance to eat that stilton sandwich in Up All Night. Not the way to get a first date off to a great start, Remus accidentally feeding her something she's intolerant to, her not wanting to say anything and spending the rest of the night in the lav.