A good one........I'm not sure if she was prostituting herself or not, p15 shows money on the bed, so I think it might be the case..........but still, all her and all sex, one on one loveydovey to begin with and slowly warming up to some bondage play, sex toys and finally a gangbang with looots of guys gettin' in on her...........good stuff, thanks for all the effort and sharing :)
Youmu does sell herself out. In the opening pages Yuyuko talks about making money. Right about where Youmu starts freaking out is where Yuyuko mentions it's by having sex (prostitution). When Youmu shows up naked a bit later she comments on how did she find herself in the situation. The male patron mentions "This is that kind of place that offers that kind of service, right?" and the rest is pretty much as you see.
So yeah, the prostitution tag here fits the overall theme.