Hmmm. In my playthrough, Ash is friendly with Iris, but since Ash avoids degenerate stuff, Iris' ending is just her with Doug.
Maybe it needs more than being friends to corrupt Iris.
If you want to corrupt Iris there are 2 main corruption paths.
Path 1
1. Don't out her to Eric when you meet her with Jack & Tyrone in bar 1st time.
2. Take photo with Jack with gets caught by paparazzi.
3. Don't ask about her father
If you do all this now Iris sees Ash as a role model & close friend.
If you go to Tyrone party Iris is corrupted. If you don't go then Iris never gets corrupted & end up with Doug. This is the main & only corruption route of Iris. Whether she ends up with sex partner of Tyrone or sex object of his friends depends on Ash choice who she has sex with at the pool party.
Path 2
1. Don't out her to Eric when you meet her with Jack & Tyrone in bar 1st time.
2. In the beach make out with Jack with gets caught by paparazzi.
3. Make out & maintain FwB relationship with Doug (Iris crush)
4. Make sure Ash lets iris knows she loves the sex with Doug.
5. Ask about her father (lose a Iris point but gains some flavor text)
If you do all this now Iris is competitive with Ash & sees her as a role model & close friend. You can check this by choosing the phone dare in the club with Jess, Jack & Tyrone.
If you go to Tyrone party Iris is corrupted. If you don't go then Iris never gets corrupted & end up with Doug. This is the main & only corruption route of Iris. Whether she ends up with sex partner of Tyrone or sex object of his friends depends on Ash choice who she has sex with at the pool party.
Sub corruption path is if you help Arthur have sex with Iris making her his sex slave. Basically this is part of the full AshxArthur arc & can include one of Ash friends in a sort of mini harem.