[What, they can do both at the same time? This knowledge is going to change Chekov's life!
Since neither of them have immediate plans that involve leaving, he kisses back softly and lingeringly, fingerings coming up to trace her cheek. He'll tell her everything eventually. There aren't any great secrets (he hopes that she knows that and won't think that he's trying to hide something), it's just a lot to talk about right now. Everything is a lot. He should have put the love thing off until later, but.
But there's nothing he can do to take that back, it's not regrettable, and maybe it wasn't exactly the wrong time to say it.]