The scene is caused by a third party, but there is not consent from the girls involved. (Ex: A guy forces a girl to have sex with another girl.)
Series Page
Rating: 4
Yumi and another idol have lesbian sex with each other in an attempt to prove to Mr. Baek that they are no longer fighting.
Eventually, Mr. Baek joins them for a threesome.
Series Page
Chapter Link (Pages 219-224)
Length: Long
Stays Yuri: Male Watches + Male Joins
Rating: 4
Kyouka and Yuika are forced to have lesbian sex with each other by the group of guys.
Afterwards, the guys join in for an orgy.
Series Page
Chapter Link
Rating: 5
While the group is playing the King Game, Ryan’s stepmom is forced to lick Irene’s nipples 5 times.
Later, Irene accidentally commands the stepmom to have sex with her for 5 minutes.
Series Page
Chapter Link
Rating: 5
During a swap, Nicole and the MC’s sister, Natalie, have sex with each other.
Series Page
Chapter Link
Rating: 4
At a swap meet, Emily and Lily are forced to have sex with each other.
Eventually they join in with Nova and the other guy there, and it becomes a foursome.
Series Page
Chapter Link
Rating: 3
The cover image is of Miku groping Satsuki in a swimsuit.
During a shoot, Miku teases Satsuki with a pen as a sex toy. Satsuki gets upset about it and the scene ends.
Series Page
Chapter Link
Rating: 4
Ken tells Liz and Sylvie to have lesbian sex with each other before he joins them for a threesome.
Series Page
Chapter Link
Rating: 4
Sana and Shiramine have lesbian sex with each other as part of a competition.
Sana is briefly shown to have had lesbian sex with girls in the past.
Series Page
Chapter Link
Anime Version: Episode 7
Rating: 5
Hitomi and Eruza get put under a aphrodisiac and they start making out and grinding against each other.
Series Page
Chapter Link
Voiced Chapter (Live Reading)
Rating: 2
In an extra chapter, Chizuru and Sumi kiss each other in front of the other characters to escape a room.
The live reading I linked is of the voice cast from the anime reading the chapter at an event.