If a guy doesn't ask for your phone number, does that mean he's not interested? I've had a pretty big crush on a guy from school for a while now, and it seems like he *might* be showing signs of liking me back, but he's never made an effort to contact me outside of school.
Is that the only sign I need to tell me that he doesn't feel the same way? He's definitely not a shy guy, so I can't really see any other explanation. But at the same time, it's hard to overlook some things that seem like flirting (he teases me constantly, sat next to me when my seat partner was gone and initiated games of tic-tac-toe [which he let me win], and has called me an "angel" on more than one occasion). It's all just really confusing, especially since I have literally no dating experience.
Also: what's the deal with high-fiving? Is that just a friendly thing, or do guys do that as an excuse to make contact?
There are several different things complicating your romantic entanglement here, Sparkler, and I'm not sure which ones to address first. You know my usual position—if you're not grabbing at some hapless dude's ankles from under his bed while he flees in terror, then he probably likes you—but I'll try to address some of your actual concerns here.
1.) Some guys will just never ask for your phone number.
I always try to convince you Sparklefolks that a lot of people are just too self-conscious to approach you and ask you out, no matter how awesome and outgoing they seem in other situations. The gulf between "I like her" and "I will literally ask her out on a literal date, literally, with my literal mouth" is a huge one. He's clearly flirting with you, but I'll cover that in a minute. I just want to make it clear that not asking for your number doesn't mean that he has no interest. Do you know how many girls I liked, and frequently talked to, in high school, but didn't ask out? Of course you don't. It was like a shrillion girls. There were so many that I had to make up an imaginary number. The point is that there's never any specific action that determines if a dude likes you or doesn't. I know it's physically impossible for your guy to be as much of a dork as I was; I just want you to realize that asking for your number isn't a given thing that an interested guy always necessarily does. Sometimes he's just like "SHRUG," and he sighs heavily, and then he types "NOPE" in his phone instead of your phone number, followed by ":(".
2.) High-fives CAN be totally platonic, but not here.
Okay, in most situations, I would agree that a high five is sort of a "you're my bro, bro!" kind of gesture. It's very bro-worthy. On the other hand, I do high-fives and fist-bumps with anybody I'm not sure I should hug (including attractive ladytypes). Is this stupid of me? Almost definitely, because I am super stupid. But I do this stuff—even when I'm interested in someone—because I've rushed these things often enough that I sometimes just want to take it bro-slow and see what happens. In short: If a guy calls you "broseph" and belches loudly and goes to poop while you are in the room, then his high-fives mean that you're in the bro-zone. If he is otherwise very flirty with you, and treats you like a pretty pretty princess who happens to warrant the occasional high-five, then he is totes into you, and is expressing his interest in a leisurely, bro-ly way. It's all about context.
3.) Your dude just isn't sure what to do next.
I think this explains most of what's going on here. If a guy sits next to you, teases you, and calls you an angel, he is not trying to recruit you to his Smelly Broseph Fantasy Football League, so that you can sit in his living room and smell the fact that he smells like bad smells. He likes you in a different way. In this case, his high-fiving is just a sort of innocuous way to have physical contact with you, so that you can progress to touching each other on the arm, hugging, shootin' out mad babies all over the joint, et cetera.
In short, don't be too confused: I'm pretty sure this guy actually does like you, and he just doesn't know what he should do next. Even popular, outgoing guys sometimes aren't sure how to get their stupid mouths to ask a girl out on a date. I'd suggest coming up with some innocuous reason for him to text you, and then giving him your number for that purpose (homework stuff, mutual friend stuff, some upcoming event you both care about—use your imagination here). The actual reason doesn't matter; you just want to see if he contacts you later to say something like "hey sup :]" in which case you're in. Find a reason to give him your number, and you're giving him the means, and the excuse, to talk to you casually. If he never texts or calls, then this was all mysterious irony ninja tomfoolery. If he's like "hi lol," then he is not actually lolling about saying hi, or indeed about anything at all; he's just contacting you in a cool and noncommittal way, and he's probably been interested all along.