The idea that smut can be 'realistic' about intense romance always trips people up. It's not about depicting a documentary-style date night, is it? The realism comes from grounding those wild emotional swings and physical connections in recognizable human psychology. Like, in some of the darker arranged marriage stories, the fantasy is obviously over-the-top, but the core tension—being forced into proximity with someone who both repels and attracts you, the slow erosion of walls, the terrifying vulnerability—that's a real emotional dynamic stretched to its extreme. The spicy scenes then become a language for that surrender and power exchange, which feels more honest than a chaste fade-to-black sometimes.
I think the best ones use specific, sensory details to anchor the fantasy. It's not just 'he was dominant', it's the way he rests a hand on the small of her back in a crowded room, a silent claim that thrills and unsettles her. That tiny gesture carries a whole relationship's worth of unspoken history and desire. The realism is in those stolen glances, the breath hitching, the internal monologue wrestling with wanting something society says you shouldn't. The physical acts are the fireworks, but the fuse is lit by character work that makes you believe, for a moment, that someone might actually feel this fiercely.