On the subject of dude's and man's: I take a lot of character traits from people I know or have known in my life, and then kinda toss them into a blender with some fictional stuff, to create a basis for the characters. In Nicki's case, she's based on a girl who I was very good friends with for several years, and we'd always refer to each other as dude, man, buddy, pal, etc. When the stars aligned and we started sleeping together, that habit didn't really go away.
That said, I recognize that it's weird; but Nicki and Guy are both a little weird. I've been trying to downplay it a bit if you're on Nicki's girlfriend/boyfriend path, and lean into the idea that they're both trying to navigate this new reality. When they're texting each other in Chapter 9, you see Nicki trying out different pet names, while not really settling on one. I think we'll eventually see them grow into a more romantic relationship (if they're dating), and act a bit more like a couple. But I doubt the dude's and man's will ever totally go away.
