I just had a thought. Usually, when you love, you are ready to do everything for a loved one (like Yuu), you want to give her everything and even more, you are happy when she is happy, but Touko’s love showed differently: she only took from the person she loves ...
Now that isn't entirely true either, is it now?
Touko helped Yuu with her studies, she gave her the mini-planetarium projector as a present from her trip. And although many of her requests start out selfish, she inadvertently helped Yuu grow as well. Joining the student council, becoming a campaign assistant, acting in the play... those are all things Yuu initially opposed, but helped her become more independant and outgoing.
And most importantly, she taught Yuu how to love.
Now you could say most of these aren't intentional, but a give and take relationship is often not direct. Yuu gets what she needs out of Touko, just like Touko does out of Yuu.