Well, a lot of the descriptions I've seen hinge on that 'primal' atmosphere. It's rarely just about lips touching. There's usually this whole sensory overload happening – the heat radiating off their skin, breath that's way too warm, maybe even a faint growl vibrating through their chest and into the kiss itself. The texture is often rougher, more demanding, with teeth involved in a way that's a constant reminder of the wolf just under the surface. It’s less romantic sweetness and more this desperate, claiming thing, like they’re trying to fuse together through sheer force.
I remember one scene where the human protagonist described it as being 'devoured,' but not in a bad way? More like the werewolf was so overwhelmed by scent and instinct that the kiss became this all-consuming act of possession, almost feral in its intensity. The author spent a lot of time on the taste – wild, metallic, like a storm – and the feeling of claws digging into their back, not enough to break skin but enough to hold them absolutely still. It walks a fine line between passion and something slightly terrifying, which I guess is the whole point of the heat phase.
Sometimes the actual transformation isn't complete, so you get this weird mix of human lips but a wolfish tongue, or vice versa. It’s messy, damp, and profoundly animalistic, emphasizing the loss of control. That loss of control is really the core of it, I think.