Start a sex race. Long or short distance. It’s up to you to decide.
Your goal is to lock yourself in an apartment or a hotel room and to indulge in rampant passion and hedonism without being distracted by anything else.
It is allowed to: have sex in all its forms, explore each other and try new practices, hug a lot, kiss each other and talk a lot; during the intervals between sex you can enjoy sleep, delicious food and favorite drinks.
It is not allowed to: leave the apartment/hotel room, surf the internet, take care of work and other problems.
Start with a short period, for example, 24 hours. At the end of the experiment, discuss your impressions and, if you both like it, plan a longer marathon.