Can someone explain me what's just happened Please...

The small omega entered in heat, who firmly believes Kaede is his fated mate. Kaede responded to the small omega’s pheromones and almost marked him, but the tall omega aka Kaede’s pair got there into time and let him bite him to calm him. Now he noticed that despite Kaede being his pair, he never got excited to the point where his knot swelled, thus making him feel bad