I've made him a hopeless romantic who falls a little bit in love with everybody he has a positive relationship with, but he's also way meaner.
He's always down for a rumble with or without weapons. He jumps people just for the hell of it, whether because he's bored or because they had something he wanted or because they shot a dirty look at someone he cares about.
He's jokey and almost lighthearted around Pony (and Johnny, most of the time), keeps himself reined in, but he can get really mean and very much an asshole
He loves hard, the Curtis gang is his family- even when they don't get along. Johnny's his brother and the others are his boys.
Him and Steve are pretty neutral, they don't hang out much one-on-one. Him and Darry butt heads a lot, usually about Two-Bit slacking in school and how that might give Darry's brothers a bad impression, and later about responsibilities. Darry feeling slighted by Two-Bit shirking his responsibilities to his own family, and always coming over drunk to bump around the Curtis house.
Soda and Pony both have fun with Two-Bit and he's always down to take them around the East Side (Two-Bit has connections with most of the gangs so even the rougher ones usually let them pass through undisturbed)
While Soda and Two can butt heads, especially when Two gets drinking, they get over it quick.
Dallas is his best friend, usually right there with him jumping folk or bootlegging for Buck. Two is hopelessly in love with him and not at all willing to admit it; whether because he's a self proclaimed coward or Dallas has Sylvia or Dallas and Tim were fucking around, it doesn't matter.
And Two does work, he picks up on bootlegging or jockeying with Dallas, he'll play babysitter or bodyguard for most of the gangs, he's really good at faking being drunk so nobody really thinks much of his presence or memory so he hears all kinds of information that Tim is almost always willing to buy from him. Anytime his ma needs help with the bills or the Curtis's rainy day fund is getting low he's tucking a few bills away to be found; he hates responsibility and expectations.
Post-canon he gets his shit together a bit more, working more often and drinking less, indulging in less fights around the Curtis house and trying to keep tension down more than ever. It doesn't work of course. Soda runs off to Florida and Steve disappears either across town or out of state, Pony either goes to college or leaves home so it's just Darry and Two left and they never got along well enough for it to last.
(He usually also has a big crush on Pony before he leaves)
In most of my aus, even ones where Dallas and Johnny live, he's a mercenary or hand-for-hire, does all kinds of odd jobs; there's not much he isn't willing to do for a quick buck, especially as he gets older.