Or maybe secretly releasing his pheromones to trigger his heat
I have a similar question: cuz why now of all times?
he actually didn't do anything. in the novel, dane counted the days and it matches his heat cycles. grayson was not part of it. for the record, he can't do that to dane because dane is more powerful than grayson when it comes to their phenotype. grayson doesn't have power like that.
the pheromones that grayson released in this scene are the usual ones he always released everyday. he didn't do anything to trigger dane's heat cycle. i can prove that even if grayson released so much of pheromones that could affect an ordinary omega, dane on the other hand could still think straight if he smelled it. it does happened in the novel.
Dane is a dominant omega, he can even make Grayson faint so no it's his natural heat cycle
It's too much of a coincidence, I think Grayson put a heat inducer in the food