"This is a stupid idea."
"Of course it isn't stupid, I came up with it. Now come on, kick."
"It is a deeply stupid idea. I sink, Eridan. I do not have neutral buoyancy like you, okay? I am exceedingly dense compared to seadwellers."
"I'm gonna be super fuckin sweet and not jump on that opportunity to say 'you sure are,' I hope you realize the sacrifice I'm makin for your sake here. Come on, I'm not gonna let you drown, Eq, we've been over this."
He sighs and—flushed blue with embarrassment—kicks off from the pool bottom and proceeds to splash water absolutely everywhere with his feet, hanging on to the edge for dear life. You submerge a safe distance away from the flailing limbs and watch: yeah, there's a lot of energy being expended, but not a lot of efficiency going on.
"Okay, okay, stop. Here. Watch me. Watch what I'm doin."
You float to the edge of the pool and demonstrate a basic flutter kick. This is clearly going to be a long-term project, and one which will be less straightforward than you initially thought, but you are committed to getting Equius Zahhak functional in the water. For your sake, mostly. The idea of him not being able to swim is one that makes you anxious.
It makes him anxious too, evidently, judging by the intensity with which he stares at your feet. "You're vastly more graceful than me," he informs you.
"Pff. No I'm not, have you seen yourself doin those workouts, all fluid and balanced and shit? You can move like a dancer when you want to. Here."
You stop kicking and offer him your hands; after a suspicious glance through wet hair, he takes them, and you tow him through the water, getting him used to the sensation of being all the way immersed with it right near his face like that. In the middle of the pool you stop. "I wanna see you try and float."
"I told you I can't," he says, with a little edge to his voice that you know means he's nervous. "I sink like a stone."
"I'll rescue you, you gigantic goob, humor me."
He siiiighs and lets go of you, turning over on his back, and....
Huh. He really isdenser than you, or maybe he swallowed a couple pounds of lead shot when you weren't looking. You dive to fetch him and he clutches at you with considerably less poise and reserve than is his wont. "Hey, hey, hey, it's fine, it's cool, I got you, Eq," you're saying as you tow him to the edge; he's spluttering and coughing and wiping at his blue-flushed face and he looks totally wrecked and why is that adorable?
"I told you," he says when he's clinging to dry land.
"You did. Okay, that's a natural disadvantage, but hey, means you got a real good reason to get good at this in a hurry, look on the bright side."
The look he gives you is honest to fuck piteous. "Eridan, I don't...I can't do this, it's silly, you're wasting your time."
"I am not wastin anythin." You brush wet-sleek hair out of his face and kiss him: his lips are cold. "Nobody's good at shit the very first time they try it. Come on, round two, and I'll make dinner for you if you can tread water for a minute."
"A minute is a very long time," he points out.
"I'll make that curry you like."
"I can't learn in one session. It's impossible."
"With the green chiles in it that make you go all flushed like a giant sexually talented blueberry."
"What? You do." He shoves at you and you let him, and he realizes he's let go of the edge of the pool to do this and flails wildly for it; you think he's totally unaware he's actually close to treading water for a moment there, instinctively following the movements you taught him first. You grin all over your face like a complete jackass and roll over to float on your back, fingers laced behind your head, in the unmistakable pose of someone deeply pleased with themselves.
Then he grabs your elbow and dunks you, and that means you have to dive down to close a hand round his ankle, and then the two of you are having the world's stupidest, most flaily splashfight.
You make curry with green chiles in it, and you smile.