Part 1. Part 2: The things a NACG does (again, even though she knows better). (Btw: I'm going to belatedly acknowledge that this is totally heterosexually based. I'm not familiar enough with the ins and outs of queer dating to speak to where this may or not apply there.)
There's at least a few categories here, so bear with me.
Pretending to want less We all know what this looks like. The NACGs truth might be: I like him, I love him, I want to call him, I want to text him, I want to see him more than once every two weeks, I want to be monogamous, I want I want I want. She tells him: 'oh hey, sorry, I was busy' (turned off read notifications and waited four hours to answer), 'oh, hey, yeah, Sat should be ok' (she kept it free for him), 'hi, can you remind me about that brewery/song/book you told me about' (and lbh if she likes those things she probably already knew), 'can't friday, have plans' (no plans, just doesn't want to seem to available), etc. This seems normal and actually kind of expected, right?
Hiding physical femininity Every woman in a sitcom whose husband opened the door while she was bleaching her mustache. Every woman who goes through a crisis when a hot date and her period coincide. The girls who are mortified when they drop a tampon in a high school hallway, and the menopausal women who carry frozen water bottles through the office to keep the evidence of their hot flashes on the dl. Insert your own story here, we've all done it.
'Not like other girls' Ugh. You guys. This is the most egregious and the most insidious. This is something boys say to girls, and sometimes something men say to women. What they inevitably mean is 'there is a flag of womanhood that I find irritating/boring/scary and you're not waving it at me'. Or, more succinctly, 'you're like a dude, but I'm attracted to you'. (This phrase is a close cousin to 'oh my ex was crazy'.) I'm not going to address the dude part yet. (Part 3?) The problem here is when woman start using this phrase to describe themselves. (I'm a retread, as usual.) But women do say this, and what is usually means is 'hey baby, I'm a New American Cool Girl - anything about other girls that you haven't liked ain't what I'll do, promise'. It can mean I won't be like your mom, I won't be like your ex, I won't be like your best friend's bitchy wife. It always, always means that the woman who says it feels the need to separate herself from a half the population to be attractive.
This is different from the women who used to follow The Rules, btw. The NACG will 100% ask a guy on a date and be willing to pay for things. She will, potentially, burp when she and a dude are doing a beer tasting. She might send nudes to a Tinder match. She's not a lady, is what I'm saying. She's just...
well, let's return to my thesis.
She's unconsciously sublimating her femininity because we're all taught women are inferior to men.
Part 3: who the hell knows. Seat of my pants nablopomo here, guys.