How to talk to my crush?

Okay! So I like a boy... And I have trouble talking to him. I am NOT in any way a shy person, I am know for being loud, maybe a bit annoying, and outrageously outgoing. I probably get at least 3 people a day who tell me to be quite, talk slower, ect. So I have no problem with talking. My problem isn't even with talking to guys, because I have a lot of guy friends who I talk to, and because of my personality, my kindness may come off as flirting and I've run into akward situations with guys liking me. My problem is that I can't talk to my crush. I mean I can, like him and I are on track and we talk all the time, we sit together, and chat, and goof off, he takes my sunglasses, I untie his shoes. He tries to take my blanket, I try to take his jacket, ect. It's when I plan to flirt, or give him my number, or invite him to hang out that I literally just can't talk. I have tried to not plan and let what happens happen, but I don't get anywhere!! Tomorrow I want to gve him my number so we can text over the weekend, but I know I will freak out, how do I not? I want to slip a note in his locker with my number but that might seem stalkerish...what should I do??