Yuu the hard bottom
Yuu's fantasy was to touch Touko and Touko's was to get ravaged by Yuu. I think they're both agreeing on who's topping at least for their first time.
Gudetamago got this right.
Yuu's surprisingly assertive throughout the story, and even though Touko used to be the one pushing herself onto Yuu, we all know she's a big softy, and that she'd do anything Yuu asked of her. Also, do you remember that scene where Yuu "tortured" Touko when they each tried saying each other's given name? Or how she tempted Touko when she first visited Yuu's room? Honestly, there's all sorts of clues in the previous chapters.
If anyone is a hard bottom here, that has to be Touko.