They wake up, terrified, next to their their respective partners and realize they have switched bodies. Kylo and Finn somehow contact each other/face each other and figure out that the night before they switched, they had both channeled the Force during sex (so Force-Sensitive!Finn here) and decide to try it again with their new partners so they can switch back.

Awkwardness, fighting off a sex-starved pilot & general and shenanigans ensure when neither Kylo nor Finn can bear the thought of cheating on their respective partners.

Up to the author if they manage to change back!