Oh Gin gets SO rough with Aku,, calling him a pathetic pervert for wanting to be fucked by his little sister he swore to protect

I think with beast Akutagawa incest, Gin has learned things like how to manipulate and persuade people in the Mafia. After they make amends, which may take years, Gin uses the fact that the Tanizakis at the Agency have sex as a way to get Aku to let her do as she wants. Just a bunch of "Come on, Nii-san.. those siblings at the Agency do it out in the open, what's it matter if we do it in private.? Don't you want my love in every form..?". The fact that Akutagawa is desperate for Gin to stay and not leave him just makes it easier for her. He can be begging for her to slow down and be gentle but she'll just coo and kiss his cheek while wrecking his insides