Hii,
At the time of my adolescence I used to make my dog lick my private parts. It used give me immence pleasure as it stimulated clitoris.Now I'm 33. I'm having fertility issues like poor endometrial receptivity. Presence of NK cells found in biopsy.does it have any relation with my previous act?

From what I quickly read I would answer mostly likely no. The normal flora in your vaginal canal should have been able to take care of any intrusive bacteria from your dog's tongue. It is likely coincidental that you're have fertility issues and you let your dog lick your private parts.