I don't think there's enough to the idea to make a good story too but enough to explore lewd ideas.
I like to think the setting is one of those Maze Crawl games where as the party find themselves trapped and for good measure naked. Maybe all female or some male.They explores the dungeon they find boxes of food and water waiting for them.
They find the food is inedible hard brown sticks that hurts their teeth when bitten into big enough to be used as a dildo. There are also packets of flavor powder that have no taste to them.
With the box are instruction that explains that the food is activated by vaginal fluid produced by masturbation. The powder is also activated by vaginal fluid and can be up in the vagina to add flavor to the food stick.
After a could of days not eating some actually tries this and it works causing the females of the group to grab food sticks a desperately play with them selves. Any guys among the group would have to eat a food stick that another female prepared for them,
Maybe to keep up with the Using Insertion theme they find puzzles and doors that require insuring something in a vagina or a female humping it to open. Like all doorknobs are phallic and will only open of grabble with a vagina.