Yeah... gonna go with tsundere there. Talking about a girl who shares room, bath and bed with someone who's very, very obviously in love with her and not hiding it, so "she's actually not interested" isn't exactly what strikes me as the best interpretation.
Of course, the fact that they're both over-the-top in their respective category is part of the humor, which not everyone will like.
Also, I guess I might relate a bit too much to the girl who likes romance in 2D but is disillusioned about things being as nice in 3D, and so pretends not to be interested.