Raph isn't a big fan of candles, to be honest. They've got their uses, of course, but ever since Donnie got the power working right since they were kids, he hasn't been a big fan of squinting by blurry, feeble light. Electricity works just fine for him, and he doesn't see the need to fuck around with weird-smelling wax. 
He likes Leo's candles, though. He likes the way they smell on Leo's skin, he likes the way Leo's eyes narrow in concentration as he lights them, he likes the excitement in Leo's eyes as he babbles about his collection. He likes the way Leo looks in candlelight, the elegant ripple of light over his scales, the way he seems to shimmer and dance in their faint glow. 
And he very much likes kneeling by his prone brother's side, watching fresh wax splatter over his scales. Leo tenses as it pools down his sensitive bridges, a few drips falling down onto the plastic sheet he insisted on lying on because the guy is a pathological neat freak. 
Elsewhere on his body, the wax is already starting to cool, so that even when Raph pulls his hand away Leo continues to pant and squirm. It's a beautiful sight, made better by all the needy pheromones flowing from Leo's body to mix with the scent of wax. 
He has to pause and touch himself for a few seconds while the next candle melts, hand shaking a little as he fists his cock. Leo looks good enough to eat spread out like this, a living, breathing cake waiting, needing to be devoured. It takes everything in Raph not to fall on him here and now. 
But he contents himself with watching the way the sensitive scales stretch and hum under the wax, how Leo's break picks up a little as it drips, drips, drips off his scales. Then Raph picks up another candle, watching pale droplets fall to the carpet--Leo will bitch at him later, and Raph will get an excuse to shut his smart little mouth again. 
"Ass up," he orders, and Leo obeys as he can, pushing himself up a little, gasping as little crumbs fall around his body, plastic crinkling underneath. He gives Raph a good look at his ass, already a little bruised from the night's activities, but nowhere near what Raph has planned tonight. 
After a lifetime of struggling, he still feels a little shocked by how easy it is to make Leo obey, now, at least in the bedroom. Raph wasted a lot of his time whining and demanding, kicking up the tension with every word, but the real trick is acting like you've already won the fight, to phrase the orders as inevitable. 
It helps that Leo's a horny little motherfucker when you strip all the fine airs aside. He tenses as Raph slides behind him, shoulders tensing slightly with anticipation. His cock is half out and growing larger before Raph's eyes, degradation sending his body completely haywire. 
Raph pours the wax right onto his ass, eyes narrowed in concentration as he paints a cute little heart right on Leo's cheek. Leo bites his lip like Raph can't see the barely suppressed moan, can't see the drool. His tail flaps like a signal flare for more, and Raph is happy to provide. 
Leo cries out as the wax pours onto his tail--not pain, although by all logic it should be, considering how damn sensitive the things are. Leo bit Raph's tail once and it hurt; Raph had nearly broken a paddle disciplining him. Leo had gotten off on that, too, of fucking course, although it had been worth it to see the way he blushed when everybody saw his bruised bottom the next morning. 
But there's no one here now and Leo is letting it all loose, the strange lovely patterns of his brain dancing with light. He shudders and twists, scales rippling with unraveled tension, making sounds that are sweeter and more obscene than Raph's ever heard before. 
Raph just has to touch himself with his free hand, movements almost frantic. He's not even touching Leo, but the two of them are caught up in soft glowing threads of want and need, and it might drive Raph if he lets it. He wants to let it. 
Leo's cock is all the way out now, hard and glistening, and Raph doesn't think. He flicks a few drops, yellow glistening against purple and Leo jumps like--well, like he's been burned. He screams, but there's no pain or outrage there, just blazing ecstasy, maybe even joy. It's beautiful. 
Raph has to cum then, white ropes of cum lashing across Leo's body to tangle with the wax, crusting and hardening there. Maybe the thought of being claimed like that, marked, owned, if what sends Leo's hips rubbing frantically against the ground, needless of his poor cock's condition; Raph can't decide whether he wants to deny him before his brothers come wailing, fractured pieces of his new shell falling from his scales like snow.