If you actually like yuri, you can skip this shit. It isn't worth anyone's time.
The girls never do anything beyond playing being a dog or being tied respectively. There is ONE sex scene with one for the girls, it's a flashback of one of said girl's male "dogs" fucking her. There is a time skip and the girls met each other again and their relationship is still just that: One gets to be a dog and the other gets to be tied.
Nothing. One girl only wants to "take care of a dog" and the other only wants to "tie people up". There is even a chapter in which is made explicit that there is nothing sexual going on between them. The ending is both of them getting together on those same terms. It also has shitty drama that is resolved off-page