You get this incredible push-pull dynamic. It's not just desire, it's this raw, primal fear of what he might become. The internal monologue practically writes itself—'My heart is hammering, but is it from wanting him or fearing his teeth?' That hesitation before their lips touch, where she's literally holding her breath, wondering if this is the moment he loses control. The author can stretch that second out for pages. The best ones layer in sensory details: the heat radiating off him, the low rumble in his chest that could be a growl or a purr, the sharp scent of pine and something wild. It makes you ache for the contact but also brace for violence.
I'm a sucker for when the tension comes from the human's side, not the wolf's. She's forcing herself to be brave, to accept this monstrous part of him, but her body is screaming with every instinct to run. The kiss becomes a test, a surrender, and a leap of faith all at once. You're waiting for the flinch, the cut lip, the taste of copper. When it finally happens and it's just tender? The relief is its own kind of catharsis.