Promposal ideas??

So this guy I like and he likes me he lives in In a diff state thats like a 18 hr drive. Anyways so I was on FaceTime him with him the other day and we’re really close so we talk about everything and I was like oh I don’t know how I’m going to prom with still. And then he was like oh go with me and I was like in Florida? And he was like oh no not going to mind let’s go to yours and I was like oh yeah sure let’s go out and like yeah. So he’s going to come to New York for my prom and to stay with me for a like a week but i also want to ask him to prom my way even tho we know we going together i wont see him till then so how should i ask over ft?