Eddie is in the Navy and married unhappily. For the sake of his children (3), he's sticking it out in his marriage. To keep himself sane, he steps outside his marriage occasionally, to assuage his active libido. Since he refuses to engage a hooker, he tries to develop fleeting relationships with non-professional women, but those who appreciate his sexual acumen. These trysts occur at different places around the world.
This is a different variation of the same kind of theme as "Bet Your Sweet Ass." In this one, though, the siblings are in lockdown due to coronavirus, parents and her boyfriend are quarantined elsewhere, and the brother and sister are a little slower, more hesitant in pushing their luck. A little.
A Damsels in Need Story Toby and Grace were thrown together on an extended work assignment away from home. Toby attracted women easily - they threw themselves at him, and he fucked them rather than send them away. Grace was sexually innocent, and became curious at what was happening between Toby and his women - listening and masturbating next door. Her curiosity got the better of her, and her sexual education was rapidly expanded by Toby.