I love how she happily indulges any of P-san's requests and how generally assertive she is. P.23, after rubbing her pussy all over P-san's body she asks him to reciprocate with his dick (and insisting she really wants it). I think it's the first time I see this sort of scene, at least in a vanilla context. The facesitting (esp. p.18) is a beautiful and rare treat as well.
I couldn't find a favorite Tsurui doujin until now but it might be this one.