How/should I ask him to homecoming?

I met this boy at camp this summer and his mom is one of my teachers. He goes to a different school and isn't going to his homecoming because his school is huge and they have a ton of dirty dancing. Anyway, I was thinking about asking him to my homecoming cause our school is rather small and there is just a little dirty dancing. So, I don't know if I should ask him. Even more so, I don't know how I'd ask him. We can't text cause he doesn't have a phone, but we do snapchat daily. If I do ask him(do you think I should?) how should I ask him. It's gotta be through snapchat, but what do I say? I want to do it casually and not just straight up ask him. Please help!!! How should I ask him? Or do I just not ask him? I have the biggest crush on him ever!