So how're the NTR scenes in this game? I remember on early versions that depending on dialogue choices, you can date Ann but if leaving other guys unchecked they flirt with her. With the right/wrong dialogue choices, would that leave Ann vulnerable to other guys?
It really is up to you.
Ann has several path; love, corruption (with sharing if you want), hate.
Vanessa also has several path, one of which apparently giving you the option to also fuck Ann in the future.
Technically speaking, for Ann, it is not NTR, as you need to make the choice to not like her, and as such state she's not a love interest to you anymore.
If I'm not mistaken, you've got two important choices: 1 The bar date with Vanessa or Ann, two: confirm whether you like her or not to her face.