Okay so Summer Days has a Light Novel not a Manga, blame MAL for my Confusion. However Cross Days has a Manga and it actually includes a Threesome ending.

If this is acceptable here maybe someone should add the Summer Days Manga? at least that one seems more likely to have some Sekai/Setsuna material?

Why is the main School Days Manga even here?

I was looking for Doujins of Setsuna and Sekai, I didn't think the actual Canonical Manga would be Yuri enough for this site.

How many people cruising this Tag on Dynasty Scans also listen to the Sailor Business Podcast?

"Trap" as an Anime/Manga literary term is not meant to be taken that literally. A Trap is any character we are told was assigned male at birth even though they are clearly drawn the way way you'd draw any other flat chested girl. The vast majority of characters the term was coined to describe are not intentionally deceiving anyone in the actual text of the story.

I think the last page is being commonly misunderstood, I don't think that blond Senpai is with is the protagonist of the first half but some a random girl, it establishes that she's into sleeping with other girls.

I've been told Reverse-NTR stories usually become Threesomes, but I don't know if that's true since it's not easy to find them.

"The game let's you pick if you want to play as a girl or a guy, and, pretty much they didn't change anything regardless of gender so, if you are a girl, it just gets really gay"

Like Grand Order. It annoys me that the Anime adaptations always default to the male player character,

I can't help but love this story. Senpai might be one of my favorite Femme Fatales ever.

This is a personal favorite Yuri Doujin of mine. I cited it in a post on my Blog last year.