Idk how y'all can look at Denji's face during that chapter and somehow interpret it as him kissing her.
Chapter 167, page 10: Yoru kisses Denji.
Page 11: They stare at each other for a beat.
Page 12: Full page spread of Yoru kissing Denji again while fondling his genitals. Notice Denji not attempting to pull Yoru's singular hand away from his genitals.
Page 13: Another full page shot of the both of them retracting slightly, to reveal that both their mouths were open. Notice Denji not pulling away.
Page 14: Denji does not attempt to pull away for three panels. The second panel involves Denji's eyelids lowering. Both their heads are moving during their makeout, Denji's never moving away. His mouth is open, interlocking with hers however imperfectly.
Page 15: Denji climaxes. Denji has weird o-faces (cf. ch. 136, p. 14), but that's probably a normal one.
In this chapter this guy isn't even sure if he's happy or unhappy right now
He has literally said, in his candid thoughts, that the handjob made his heart feel good even though the act itself didn't feel as good as when he did it himself.
If it wasn't clear that he liked it in the chapter that it happened-- where he was fully participating in the act-- page 5 of this chapter sufficiently disambiguates his current emotional state. Me personally, I know that feeling of having my first make-out, having it end awkwardly, and being zoned out for
at least the next day, not knowing whether to feel happy or unhappy but at least knowing that I felt preeminently emotionally "warm" during the act. It often comes with the territory of not used to that level of interaction with another human being, not expecting such a thing to be your lot until several years out-- if ever.
At least part of the reason he can't tell if he's happy or unhappy is because that alleyway handjob (and the sushi in front of him) is the speck of light in the morass of his current life where he lost all of his pets, doesn't know where his kind-of daughter is, was disassembled then reassembled, got kicked in the nuts almost immediately after waking up
twice, and is still so much of a slave to lust that he rationalized going to a brothel while having already resolved to look for said kind-of daughter.
Explain to me this, so far Denji's life is the worst its ever been. He just had a breakdown over thinking with his dick as an easy means to escape reality. What does him consenting to a handjob from Yoru do, thematically, for this story at this very moment?
We can only fully appreciate how the narrative expresses the intended themes after it's complete because we don't know what's going to happen next. There's also the possibility that it's underutilized or completely wasted, or even that Fujimoto literally
just wanted to depict Denji getting jerked off by an amputee in an alleyway because it'd be funny.
So far, however, Denji actively expresses the export of that incident early on in this chapter, which is both consistent with his earlier impressions of Asa as someone he's comfortable with that hasn't (as far as he knows) jeopardized his life like all the other women thus far (cf. ch. 120, p.4-5; ch. 149, p.17-18) and also suggest a development of thought in regards to her. In this chapter, Barem's exposition about the mindset of devils also suggests that Asa is becoming more devil-like, which also implies (as others have conjectured based on other hints) that the identities of "Asa" and "Yoru" are merging-- meaning that despite Yoru technically being the one to make out with Denji, who's doing what is certainly not as clear as it was earlier in Part 2. Accordingly, this is still in the continuum of development for Asa and Denji's relationship.
At bare minimum, this is what that sequence was about, meaning that it's also relevant to how this narrative explores sexuality by way of examining the protagonist and the current deuteragonist.
That's not a straightforward answer, but I'm no prophet, and the above makes much more sense than the idea that we're exploring the prospect of male sexual assault or whatever while the narrative emphasizes Asa/Yoru's tsundere cope and Denji thinking about how emotionally fulfilling the alleyway handjob was-- because at that point you'd
also have to argue that Fujimoto's poorly and indelicately executing that vision.
