Damian doesn't concern himself overmuch with sex. He knows that as Batman, he won't be having much, even if in other ways he chooses to follow Grayson's example, because even Grayson's been celibate since he put on the cowl. He knows that his parents had sex, but it's so far removed from his lived experience of them that it's something of a shock when Father faffs off to Europe with Selina Kyle and Grayson subjects him to an egregious display of winking and nudging and applauding Father's good sense before it occurs to him that perhaps Damian would prefer not to know what his father gets up to with women who are not his mother.
When Damian turns thirteen, Father attempts to subject him to what Grayson has colloquially termed The Talk, but as Father is about as emotionally expressive as a cabbage, he simply says, "Always obtain clear consent from your partner and use condoms at all times," before he pulls up the cowl and stalks to the car.
Alfred harrumphs in the background and in the morning attempts a more rigorous discussion of the topic, but Damian will have none of it.
"I understand the reproductive process, Pennyworth, and will engage in it when it becomes necessary to produce an heir."
"I see," Pennyworth says, and Damian has the unfortunate sense that he does, far more than Damian or Father would like. "Then I shall say no more on the subject."
Damian unbends enough to reply, "I appreciate that."
So it falls, as most things have, to Grayson to quiz him about his alleged crush on the alien and his appreciation for the many strong women they meet in the course of their work.
It's not that Damian doesn't have the urge, doesn't wake up breathless and sticky after dreams he can never articulate, or that he doesn't take matters into his own hands when the need arises. Despite his genetic perfection, he's still a thirteen-year-old boy.
When Damian masturbates, he always starts out thinking in the abstract--breasts and hips and thighs--and then drills down to specifics--the way Cassandra's body flexes as she fights, the long line of the alien's legs as she flies, the utter grace with which Grayson moves (he's annoyed by this not simply because he's come to think of Grayson as a friend, but because it gives him something in common with Drake, whose obvious infatuation has never quite dissipated, though no one speaks of it). But somehow his brain always zeroes in on one person at the moment of truth, and as his tension reaches its crest and breaks over him in waves of pleasure, images of Stephanie's blonde hair and full breasts, the strength of her thighs and curve of her ass, race through his mind's eye and he spills himself over his hand with choked off moans.
"It is intolerable," he tells Grayson when the man insists that he team up with her in the spirit of their newfound (and now sorely tried by Damian's stupid hormones) amity. "She's a liability. Her ridiculously bright hair, for example--not only does it make her stand out in the shadows, but wearing it loose gives opponents an easy handhold during a fight."
Grayson smiles, which is always disconcerting when he's wearing the cowl. "Her hair is pretty," he says, as if that is a concern.
"You shouldn't be noticing whether her hair is pretty," Damian snaps, "but whether it will endanger the mission."
Grayson laughs. "Don't worry, Damian, I won't hit on your Batgirl."
"Tt. She's not my Batgirl."
"If you say so. You might have to watch out for Tim, though."
"Anyone who has the bad taste to get involved with Drake deserves what they get." It's more of an effort than it should be to keep his voice level; he doesn't try to keep the sneer out of it.
Grayson hums noncommittally. "I'll make sure to tell her that. But for now, you're going to be her backup down at the docks. I've got to deal with Two-Face."
Stephanie grins at him when he arrives, which is not the usual response people have when he shows up. As always, her mouth is bubblegum pink and she smells of sweet things--tonight, it's maple syrup and Kevlar--and he gets uncomfortably hard after a few minutes of being hunched next to her on the ledge of a warehouse. The fight that soon follows helps, allowing him to channel his energy into beating up thugs who would fill his city (already, he thinks of Gotham as his, and he hopes his loyalty to her will help him win his father's favor) with guns.
Afterwards, Stephanie still smiles, though her lip is split and she walks with a slight limp. "Pizza?" she asks, and the genuine hope in her voice makes him want to say yes, say that he'll do anything she wants him to as long as she keeps smiling and talking to him like that, and maybe lets him touch her--
He leaves without elaborating, though he hears her weary, "Rude, much?" in his ear as he swings away.
Upon his return to the cave, he jerks himself viciously in the shower, one arm braced against the cool tile, ruthlessly suppressing images of her pink mouth moving over his skin, the heat of it wrapping around him while he thrusts, the bright gold of her hair spilling over his skin. He comes breathlessly, angrily, and though his body is loose now, the tightness in his chest remains.
"Robins and Batgirls," Grayson says with a shrug one night soon after, "it's a thing." Only someone who's studied him as closely as Damian has would see past the false nonchalance to the sadness in his eyes.
After that, Grayson favors him with knowing looks but says nothing until the night Steph is poisoned by her father. When Oracle gives them the news, Grayson squeezes his shoulder gently and says, "Go."
Damian is gone almost before the word has died away into silence. He keeps vigil outside her hospital room for hours, the tightness in his chest unbearable, the need to move, to fight, overwhelming, though there's no way he can fight this battle for her, and she wouldn't want him to even if he could. The ache eases only when she wakes, but the memory of it lingers like a phantom, flaring up every time thinks of her.
"I told you she was a liability," he says when he returns to the manor. There's a small, inexcusable tremor in his voice. Grayson responds by pulling him into a hug. Damian hates himself a little for relaxing into it, his body choosing to ignore his commands yet again. "How do you stand it?" he whispers, dry-eyed and dry-mouthed, his whole body wrung out from tension and its stark relief.
"You just do," Grayson answers, which is exactly the kind of useless nonsense he's given to spouting. "It's better than not caring about anyone at all."
Still, Damian checks up on her for a while, both during her recovery and after her return to active duty, careful not to let her see him. When she finally does catch him, her smile is wide and brilliant.
"Hey, Robin, you wanna punch some bad guys and then have some waffles?"
"Yes," he says. It's the least he can do.