If the scene starts as fully yuri, but eventually a male comes in and joins them. (The “Male Involved” tag is only used if the male is involved from the beginning of the scene.)
Series Page
Chapter Link (Pages 51-64)
Rating: 4
The MC has a foursome with Aoi, Lilliana and Midori.
On Pages 54 & 57, Aoi and Midori are briefly shown having lesbian sex in the background while the MC was having sex with Lilliana.
The MC quickly rejoins afterwards, so it remains a foursome for the rest of the scene.
Series Page
Chapter Link (Pages 43-48)
Rating: 5
Continued from the previous scene, for 1 page, Lilliana and Cassia have a lesbian threesome with Aoi in front of the MC.
Afterwards, the MC joins and the scene turns into a foursome.
Series Page
Chapter Link
Rating: 3
2 of the FMCs briefly have lesbian sex with each other while a group of men watch.
After they finish, the men join in, turning the scene into an orgy.
Series Page
Chapter Link (Pages 49-55)
Rating: 4
While the MC has sex with Suiren, Aoi has lesbian sex with Touka.
After they finish, the MC rejoins and has sex with Touka again.
Series Page
Raw Chapter Link
Rating: 2
1 of the FMCs briefly uses a dildo another girl before the MC joins them.
Series Page
Rating: 4
Kina briefly gropes and teases Railey’s body before the MC eventually joins them for a threesome.
Series Page
Rating: 1
Kina and Railey briefly hug each other while nude.
Series Page
Rating: 2
Lina gropes Yoojin’s breasts in front of the MC before he eventually joins in and gropes both of theirs as well.
Series Page
Chapter Link
Rating: 5
Alice makes out with her sister, Irene, and briefly begins to seduce and have lesbian sex with her.
They eventually stop and look towards the MC, turning the scene into a threesome.
Series Page
Rating: 4
After the MC finishes having sex with Maya and she tilts her head back, the MC quickly escapes and swaps out with Amber.
Amber then ties Maya up and has lesbian sex with her.
The MC rejoins in the next chapter, so I have this tagged as Male Joins.