"Because it is hot out, we are in full sun, and you are doing physical activity." Dark replied laconically. "If you had been running on a track, you would not question it."
Dark and Daizi did spend some more time in the water together, although Dark got out first, sitting on the edge of the boat with his feet in the ocean, drinking water and watching his wife. It had only been three days, but whereas the twins had subtle burns they were treating with aloe, he had tanned significantly, although his was less obvious than his wife's, because her bikini top left evident tan lines. She didn't stay in the water for as long as she might've liked, because she knew everyone else was on the boat waiting for her, so eventually she climbed back up, dried off, and Dark more or less made everyone line up to reapply sunscreen.
When Dark drove them around for a little while, Daizi found the most private spot she could find and turned her back to everyone else so she could nurse, allowing herself to daydream they were, in fact, on a dramatic adventure. Maybe pirates, maybe exiles, and as she fed her daughter, she told her all about Danae, mother of Perseus, who gave birth to him while trapped in a wooden box and set out to sea, and how Danae would've fed her baby while the waves rocked them just like this, and how big and strong Perseus grew up to be. "You can be a hero, too, Hummingbird," Daizi cooed, forgetting everything else for the moment, "I bet you will be."
Once her baby properly fed and comfy, she turned back around and asked, "Can I drive now?"