They break apart as they hear a wolf-whistle.
"Looked like you were enjoying that, mistletoe or not!" Lily cackles.
"Shut up; we're just friends," Rose says, avoiding Scorpius's eyes. Officially, they are just friends, but they had to kiss to get rid of the charm on the mistletoe - maybe they carried on for just too long to fool anyone...
They're still trying to fool themselves, too. Though Rose doesn't want things to change, she's beginning to realise this: soon, they'll have to accept that their encounters in broom cupboards happen far too often for them to be just friends.