I really like Jaclyn Friedman's quote that says,
"Consent is not the absence of a 'no'; it is the presence of an enthusiastic 'yes'."
To me, in the scene shown, there's a very strong "no", but some people are arguing that Sei had his own reasons for initially refusing. Not because he didn’t want to have sex, but due to emotional reasons, and then gave final consent. This interpretation shocked me a bit, so I decided to revisit the episode and bring it here, trying to analyze only this scene without considering the previous discussions about Fuji’s abusive behavior.
Fuji never even touched Sei before, and in the scene we're discussing here, he, in a fit of rage, aggressively grabs Sei, throws him onto the bed, and pins him down. Sei then tells him three times to let go.
When Fuji kisses him, he says again, "Let's stop". His face shows discomfort.
After that, Fuji says something to hurt him emotionally by bringing up the fact that he didn’t want to because he had already satisfied himself with another man.
Then Sei says the following: It doesn't matter who it was, right now...

An expressed refusal, with all the words.
And then again...

And now, the convo that made people forget everything that happened in the last 3 minutes of continuous sexual harassment.
F: Why?
S: Because there'll be no coming back.
F: Go back? Back to what?
And this is the face Sei makes as the scene ends, with Fuji kissing his neck while he looks like this.

He didn’t consent, he GAVE UP. That’s not the face of someone who's enthusiastic about doing sex.
Now quoting Bell Hooks
"Love and abuse cannot coexist."
The next day, Fuji apologizes for hurting Sei, and some people are saying it was rough sex, when it was explicitly rape. He used force not because he was overwhelmed with passion, but to pin Sei down while he was telling him to let go. It was literally shown.
I don’t understand how there can be multiple interpretations of what happened. I mentioned media literacy in the forum title, but do you really need deep prior knowledge about the nuances of abuse when everything I described and that was shown actually happened? My analysis was visually descriptive.