i think Erryn works in that Club as a Stripper in the VIP Area to affort the Apartment she has and don´t wants anyone to find out about this.
but somehow this ethan found out and blackmails her now to do modelling for him.
well she somehow told that the appartment is quite expensive and i doubt that she can affort that appartment with part time moddeling after school.
she thought (i wish i could) when Melissa told her she should focus on school and Modelling can come later.
and the scene after erryns phone call could play out in many ways.that scene after the call was too short to know what happend after the ass groping from that old guy.for all we know she could have slaped him in the face shortly after or yelled at the old fart or something.
and of course erryn would or could wear expensive dresses she is moddeling and sometimes models wear expensive dresses to show clothes to some old fart costumers
i think that whole beeing an hooker,prostitute,escort or an elite escort girl thing is nonsense it not fits in the game.
that does not mean that there could not be some Pervs or old farts groping modells or she must do some "Special" Stripping sessions in the VIP room mixed with some modell show or something as part of the blackmailing.