A lot of this series, but this chapter in particular, is very well executed in a very on-brand Mochi mix of dirty and heartfelt. Toudou's denial of being a lesbian/into yuri is of course blatantly contradicted many times by now, but her construct of self-justification is also constantly attacked. We have seen her slip up about Yomotsuka in particular several times now (admitting she is her crush even before her supposed beloved teacher, admitting she enjoyed her molestations, finding her cool etc.), to the point where it is clear that she is more or less the "main heroine" if we went by harem terminology.
But Toudou still continues to cling to "I am just humoring her, because there will be (non-gay) benefits to me." Yomotsuka is rich and influential, so it is actually halfway believable that a scummy person would want to use her infatuation for her own gain. Yet the maid in this chapter completely throws this out the window by showing that if she were in an open relationships with Yomotsuka, her life would actually be in danger and she immediately is scared out of those self-serving thoughts. The ticket is her reason for being there and would be enough to justify doing something perverted in her mind (she braced for that much), but going any further would be at her own peril.
Yomotsuka's favor is entirely non-sexual however. She has been portrayed as a hardass and eccentric already equally, so it is clear she has a no nonsense attitude about her weird requests. Her skill at molestation in chapter 1 and her clear skill at sex in this chapter show that she seems more than familiar with lesbian intimacy, which explains why she was barely shaken by the fact that she was sexually attracted to Toudou after the potion wore off. Still, she just makes a banal (if eccentric) request. So all the sexual tension has to come from Toudou's side, who clearly got her hopes up and was more than willing to go along with it in the end.
What I find very important is that this first time was not under the influence of the love potion and that both sides consented completely. The story is entirely founded on a scummy drug plot, yet the genuine feelings and desires are those that matter in the end. The love potion is merely a jump-start to close a gap quickly and lead to realizations about the true nature of Toudou's sexuality. We have come to a point where Toudou has to either accept she is into yuri or turn sex and romantic affection into a "reward" for "playing along" with her victims/aggressors, much like her fantasizing about riches or influence used to be.
Although I wouldn't necessarily enjoy her sleeping her way through the roster of girls like an eroge harem protagonist, this is Mochi, so I will simply accept that it comes with the territory. I will insist, though, that Yomotsuka holds a special place in Toudou's heart as the only one she actually has shown serious romantic interest in. Giving all her firsts to her is certainly a good indicator that Mochi has the same idea.
I've been re-reading the manga and it's surprising how many times Toudou brings up Yomotsuka. It's in almost all chapters. When she's touching her kouhai she thinks about how Yomotsuka's touch was on another level, she threatens Shirashiro with telling Yomotsuka about her sword and it's dissapointed when Sports Girl's groping skills don't match up to Yomotsuka's.
I don't know how future chapters will develop Toudou's relationship with the other girls, but the one who did the greatest impact was Yomotsuka for sure.
Conversely, I'm really not feeling her relationship with glasses best friend. In the case they end up going further, I can just hope Toudou enjoys herself.