I think it's meant to be ambiguous whether it's just some aggressive smooches on the cheek or something, or actually something more exciting, which is why I didn't bother with an incest tag. But yes, I'd certainly like to think that's what's going on…
Was it ever shown/hinted at in a previous chapter that there was an incest side-couple as shown in the bonus?
If it's not clear: this is the mangaka who used to go to their high school and they are now working as assistants for, and that mangaka's younger sister. I think all the scenes they appear in in volume 2 kind of give the impression that she is super possessive of her older sister and that they are close, but don't exactly make it clear that anything more is going on. Reread pages 1–6 of Ch 16 for the strongest taste of it, I guess.
last edited at Jan 15, 2025 10:00AM