Thing is I'm pretty doubtful Mikage still even needs or wants a sexual relationship with Tomoe at all.
Seeing as Mikage is neither asexual nor does she look like she wants a platonic relationship, I am betting Mikage definitely still wants the sex with Tomoe. But maybe, just maybe, she's trying to take it slow with Tomoe (pure speculation). Mikage wants Tomoe to think only of her and in a romantic way and not just like family.
Ch10 P133 (here is when Mikage says she doesn't want to be seen just as a convenient little sister for tomoe to protect/ look after)
CH10 P138 (where mikage tells tomoe she should look only at her)
The crux of this story's conflict was that on account of their pasts with their father, Tomoe had dedicated her life to protecting Mikage and placed her at the center of her life in order to (psychologically) protect her own self.
I think after their mother dies, it all went downhill for Tomoe. She wasn't trying to protect herself (yes, indirectly probably) but mostly her family which consists of only Mikage (and herself). She wanted to be in that tiny little bubble which she built around the two of them which she sees as "family" (and she's right. They are familym but her little sister is a sociopath and complicates things). Tomoe felt like she had to be strong for both mikage and herself.
CH10 P136 (This is the part where we see Tomoe breaks down and says why she feels like she could never express her true feelings like when she's sad or lonely)
But after meeting Kujou, she felt like she no longer needs to. Thats why she planned to go to a university far from their place. Then Kujou went all kinds of crazy just so that Tomoe will have her forever igrained in her memory... B-b-b-*tches be crazy!
Mikage's efforts to break out of the tidy role Tomoe had constructed for her (by sexualizing herself) ultimately came from the fact that Tomoe wasn't really looking at her.
Well, if you say she is "sexualizing herself" then she must have had a partner, and I can only think of her dad. So, Mikage and her dad did have sexual relations. But after sometime, Mikage and her dad doesn't do stuff anymore and She just goes to his place purely for helping his dad with his art by being the model, is what I think.
When Takayanagi's confession made Mikage realize that she was pushing her feelings onto Tomoe, she realized that what they both really needed was to confront each other's real feelings and accept each other, which they did. Now that Tomoe and Mikage have constructed a proper relationship, I'm not sure a sexual component between them is even still necessary
Maybe. But it all depends on how they feel, and the manga was inconclusive on the part where Tomoe and mikage got together. We have NO CLUE whether their relationship was sexual or purely platonic. We can only speculate and deduce from the past chapters of how they would be when they get together. Based on the epilogue, I thought the dialogue was subtly giving hints about their sex lives or this is just me being totally crazy (like Kujou lol) or they were really just describing what they thought of summer (sticky and oppressive) and winter (crushed by something huge you cant see)
so perhaps Mikage has in fact accepted Takayanagi as her partner in the romantic component of her life.
IF Mikage sees Takayanagi as her girlfriend or as a romantic component of her life, I don't think she would still go on that trip with Tomoe. The whole story was about two sisters, one being a yandere and some other drama inserted onto the story they had to deal with. Ultimately, the story was mainly focusing on Tomoe and Mikage's feelings towards each other.
I think Takayanagi has a chance with Mikage, but not at this point yet, because Mikage is still trying to recuperate her onee-chan's heart (which was mostly damaged by Mikage herself, oooh the irony, and Krazy-Kujou)
