So my bf and i don't go oral on each other that often. but whenever he go down on me and gulp some of my fluid he experience sore throat (like we have in cold sore throat). this only happen if he gulp my fluid down his throat. if he spit it out and do not gulp it, he does not get sore throat. Its ALWAYS happens only when he go down on me. i know its definitely not sore throat because it especially happens next day after he gave me oral. and his throat recovers after 3-4 days like cold throat do. why is that happening? i don't think i have any STI / HIV or any ST diseases of infection cause we are each other's 1st sexual patners. we also do protected sex 90% of the time. and i don't have any v.infection , i am healthy down there. so why is that happening?