Responses
Yes, but that kind of thing is usually talked about first. You don't just naturally choose not to pleasure your partner.
Take this yaoi for example:
https://www.mangago.zone/read-manga/bdsm_basics_guide/
The top/dom has trauma from being r*ped by his previous sub, so he sticks to only giving pleasure for a good chunk of the story. But they actually talk about it and the sub agrees to not do it until he feels safe. That's not one sided, that's being considerate.
Whatever reason Iseul has for her behaviour, she should talk about it before treating her partner like a sex toy

Something that always bugs me about this manhwa (and a lot of other yuri manhwas) is that when they're having sex, it's so one sided. Sori's always like "I can't hold back anymore", and then she doesn't get any.
I don't think the author has a very good understanding of lesbians. That's not how it works.
I mean, yeah the top is usually the one who takes the lead, but it doesn't mean that the bottom is supposed to just lay there and not do anything.