Look, I know this is Twilight and realism isn't the first word that comes to mind, but if you're diving into that territory, grounding it in Bella's specific brand of nervous overthinking is everything. She's not a confident seductress; her internal monologue would be a hurricane of second-guessing, sensory overload, and frantic analysis of every micro-expression on Edward's face. The physical details need to reflect that constant push-pull between human limitation and vampire... everything. Don't just describe his cold skin as a single fact; let it be a shock every time, let her notice how her warmth leaves a temporary flush on him, let the contrast drive the tension.
Also, please, for the love of all that is holy, move past the marble metaphor. It's done. Think about other textures—alabaster, polished stone in a creek, something that has weight and solidity but also potential for fracture. And Edward's perspective is a minefield you have to navigate carefully. His control is his entire identity, so a scene like this is less about passion and more about terrifying, exquisite precision. The narration should feel like walking a tightrope over a canyon, where every heartbeat of Bella's is a siren call and every movement he makes is calculated to avoid snapping her in two. The realism comes from that unbearable restraint, not from abandoning it.
A lot of writers skip the aftermath, but that's where you can really nail the tone. The morning after wouldn't be simple bliss; it'd be Bella obsessing over whether she's different now, and Edward quietly cataloging every new scent and sound of her, worried he's altered her in some irreversible way. That lingering, slightly anxious intimacy is way more true to their dynamic than any grand, flowery declaration.