[ oh god now what does she say? "You're a good kisser" is not appropriate. Commenting on it at all really isn't something she feels comfortable with quite yet - too soon. She's not even sure what she'd want to say about it; she'd much rather forget that it even happened. Except she won't.
And so, for one of the first times ever, Miwako has nothing to say to Sanji - not just yet. She's still thinking that he's over her already, but considering that she wasn't violently repelled by him - nay, actually liked being kissed (which was, incidentally, by him) - she's starting to doubt herself just a little. It's not something she'd be willing to sacrifice their friendship for; when they listened to the iPod and sat on the couch talking, Sanji convinced her to be a little less scared of Arashi, because they weren't doing anything wrong, then. And not really now, either - they had to kiss, it wasn't an option. But if it becomes a problem, Miwako will never forgive herself.
She just walks along, silently thinking about these things. They're still friends and she wants to let him know that - even if disaster strikes - she still wants to be friends with him... But she just can't find the words. ]