Oh man, this confliction Moka is currently having with Ueno & the bully trio is eating her alive. Repeatedly, Moka tries not to act too bothered hearing these shocking revelations from them, but when Moka is alone, the facade crumbles as Moka struggles to process the complicated relationship Ueno has with the bully trio, her jealously, and her lack of physical compatibility with Ueno. Learning that your two good friends have a troubling relationship with your boyfriend is a complicated situation to deal with and running a gauntlet in trying to process, figure out, and getting them to reveal the truth is a draining experience to deal with as well.
One clear-cut solution is for Moka to cut ties with Tsubomi and Chisaki, but man, those two are genuinely her friends. One bonded over tennis, the other bonded over music. When Moka was at her most vulnerable to Riku during the tennis camp arc, the bully trio ( well mostly Chisaki) did their best to ward him off during the time when Ueno was too oblivious/stunned to do anything.
Also, if Moka decides not to be Tsubomi's friend anymore, one of them is going to resign from the tennis club due to the awkward nature of the situation.
It will be a lot easier if Moka gathers the bully trio and lay out her frustrations instead of dealing with them one by one....and with Chisaki planning to talk with Ueno, Moka is going to feel restless about them even talking.
Sheesh, it was a lot simpler when Moka acted as the oblivious maiden friend to Ueno while the bully trio had their way with him.
Heh heh, those were different days...