What did Yuji do to his sister Kazuki?


In _Grisaia no Rakuen (Paradise)_ , after saving Yuji and retrieving the real
body of Thanatos (Kazuki actually), there was a scene (aboard the ship Mihama
Academy) when Yuji got pissed or irritated due to Kazuki's "bossy" attitude.
Yuji yelled "Kazuki!" and then he dragged her to some place on the deck.
Afterwards, when they were "finished" Kazuki said: "Dont ever do that to other
girls anymore..."

My question is: What did Yuuji do to Kazuki? Is there a manga that explains
this?




Really got not much reference
[here](http://tarowy.blomaga.jp/articles/65014.html) but there are two
versions to this story in the game, the safe mode where it was Yuji giving
Kazuki a shoulder massage and the 18+ mode where they had sex, not sure which
side the anime adapted but I think it is the 18+ side with that ambiguous
scene but it is totally up to the watcher's imagination here. In that link,
the commenters mentioned what they thought of the episode compared to the game
so just go ahead and read those, if that is insufficient as evidence then I
will leave the proper answering to someone else. But yes, they totally did say
that they had sex in the game.

[![enter image description
here](https://i.stack.imgur.com/NgHkV.jpg)](https://i.stack.imgur.com/NgHkV.jpg)




Really got not much reference
[here](http://tarowy.blomaga.jp/articles/65014.html) but there are two
versions to this story in the game, the safe mode where it was Yuji giving
Kazuki a shoulder massage and the 18+ mode where they had sex, not sure which
side the anime adapted but I think it is the 18+ side with that ambiguous
scene but it is totally up to the watcher's imagination here. In that link,
the commenters mentioned what they thought of the episode compared to the game
so just go ahead and read those, if that is insufficient as evidence then I
will leave the proper answering to someone else. But yes, they totally did say
that they had sex in the game.

[![enter image description
here](https://i.stack.imgur.com/NgHkV.jpg)](https://i.stack.imgur.com/NgHkV.jpg)

