This is an unrelated chapter. It's more about her ideas and feelings.
Since she's been stranded on this island, Tsunade found herself changing little by little. Becoming someone unrecognizable. Had this been because she stuck with a young, handsome ninja? Was this island bringing out the desires within them? Could she go back to the life she once knew? Never did she think she would end up in a situation like this. To end up on an island and fucking a young blonde Ninja. Had she had been in the village, this would never have happened. Nor would it have been possible. That would been too risky. But here she was with this blond stud who fucks like a champion. Providing her with a level of you for real that she had never experienced before.
At this point, she didn't want it to end. Despite knowing full well, that it started when he took advantage of her. But who could blame him? She is the forbidden fruit after all. And any man would kill to be able to fuck her. Age is just a number and Naruto has proven that.