I'm still obsessed with the Promise band idea, sorry.
The setup I imagine is that they're a punk-pop band that emerged from the wreckage of the punk-rock band Council with their hit single Bubblegum Promise(or something, i just thought it was a good name for a shitty 200s song). You're a manager/stagehand/security guy on their latest tour that ends up intimately involved with all 5 of them over time.
>Mumei
Reticent, taciturn bass player. Dresses like a librarian in her off time, doesn't like being recognized. Lines about how she's busy with college and the band isn't her whole life. hee only one where I'm not completely clear on where the sex jumps in, which sucks because she's meant to be the first one.
>Fauna
Mumei's close friend in the band, on keyboard. Mumei brings her in because of her voyeurism fetish, which Fauna is a bit weirded out by but willing to engage in. Rather clingy and awkward despite her outward cockiness and motherly demeanor. She spends a lot of time trying to take care of her bandmates, but they're not huge fans of her vegan desserts.
>IRyS
Lead vocals, known airhead. She was brought in to the band by the record company after her career as a solo singer/songwriter stalled out. Keeps making you awkward with inneundo you *think* is unintentional? Once she realizes you're involved with the first two, decides to take you for herself, something about being previously vetted raising your evaluation in her eyes. Huge tease, constantly getting you to take her on expensive dates while threatening to expose your relationship with Mumei and Fauna. Chapter ends with (You) being blueballed after she very nearly gives you road head.
>Bae
Previous lead vocalist, now on guitar. Huge complex about that, sad about her friend(Sana is obliquely referenced as being 'gone', everybody gives different reasons for comedic purposes), jealous that IRyS 'stole' her position. This leads to her wanting to 'steal' you from her in return, but she doesn't have the guts. So she gets drunk and attempts to seduce you, but ends up throwing up on you and breaking down in tears. You clean her up and take her to bed, at which point she grabs you and starts crying about not being good enough. Cute emotional moment where you cuddle and bang.
>Kronii
The drummer, only one left at this point, you try to hang out around her because being around all of the other band members is awkward for various reasons. Outwardly completely uninterested in you and men in general, something something narcissism bit. You end up running into her at the gym, obviously a bit pent up since you're no longer having regular sex with 3 girls. She 'takes pity' on you and offers paizuri, which you refuse, causing her to become upset. Something something 'no emotional connection', somethign something she takes it upon herself to prove supremacy by getting to bust inside her.
>Final chapter
The general idea for an ending would be to have a big fight where your relationship with all five is revealed and then have different min-endings for each girl plus a harem ending, but that sounds like way too much work. Not sure where to go here.