I've noticed that both times Asumi has had a threesome, it has been directly or indirectly set up by Ouka

I think saying that Ouka has set up Asumi's first threesome is a bit of a stretch. It was Asumi who brought up the topic of promotions and the one Ouka recommended was a time extension in exchange for a review. The offer for the threesome appears later on, as Asumi peruses the website. So the only way Senpai influenced this was by recommending that Asumi should have an eye out for offers that might interest her.

is it perhaps foreshadowing that Senpai only does threesomes?

Also probably not. For one she seemed totally fine with her one-on-one sessions with Miho in chapter 4 (The one where we are introduced to Ena) and the unnamed (?) girl in chapter 23 who arrives with Toki. And in the Volume 3 Extras she is booked out for one-on-one sessions with her regular.

Now to your point, Ouka seems totally fine with the possibility of having a foursome in chapter 4 as long as Asumi didn't mind, which she did. And whilst we have seen a large focus on S&M in Ouka's interests ( which we don't see in the extra so perhaps a newer passion), some of the videos she lends to Asumi in chapter 2 seem to include threesomes as well.

last edited at Oct 23, 2024 8:49AM

In case anyone wonders why the incest tag is gone, I requested for it to be removed. Reason below:
I didn't remember those two being sisters, so since I assumed there would be more things I had forgotten I read through a wiki page. While it explained Medusa to be the former co-ruler of Angel Land, there were no mentionings of any familial ties between her and Palutena. This trend continued troughout all but two of the seven wikis I checked (including some japanese ones). The only wikis which featured Palutena and Medusa as sisters/family members were an "Immortals Fenyx Rising"-crossover wiki and another one which included Pokemon amongst other things. (The latter is cited under "People also ask: 'Is Medusa Palutena's sister?'")
Kid Icarus lore may be a bit 'loosey goosey' but I think displaying correct information still matters. (Not that I blame anyone for,mistakenly, believing them to be sisters as the top answer on Google is straight-up lying)