As soon as Hirabu grabbed Sasha's ass, obviously everyone present noticed it. Sasha immediately tried to move away but Hirabu turned out to be quite strong. So she was unable to.
As for Ren, he noticed it too but was very unsure if he should stop it or not. If he stopped Hirabu then using that, he would also stop Ren from touching Uria. In that case, he would immediately lose access to this super rare and valuable lady with S rating.
As Ren was thinking about this, he looked at the reward that he was getting. And as soon as he saw that, he was able to make up his mind.
So as the four of them continued talking, both Ren and Hirabu continued to touch each other's partners. But doing just this much was something of a waste for a lady with S rating. So Ren really wanted to start doing more lewd things.
So he moved on to the next step and started to hug and kiss Uria. Just like before, Hirabu did not stop him and instead just pulled Sasha toward himself in order to hug her.
