since he has extremely good control of his pheromones from years of practice and schooling, he’s never reached a point where he’s lost himself to them to the point that he’s knotted someone. he’s actually never knotted someone before and knows the repercussions of doing it, hence why he’s a perfectionist when it comes to controlling them. so his face is more like “oh shit what did i just do?” this is years of practice that came crumbling down in just one night so his reaction makes sense.

Saw someone on Twitter that knotting is his biggest mistake. Can any novel readers tell me why, please?