I've had bad aches in my balls for a week. My girlfriend doesnt want to have sex yet our do any of that !**@! yet. So I get worked up and I dont ejactulate til later. Is it just a bad case of blueballs? Because everything is normal now. This isnt the first time this has happend. Even after I ejactulated the pain was still there and lasted for a week.
I know your woes to a similar extent, I used to practice somewhat tantric intercourse with my previous girlfriend, this would sometimes take us to sex lasting over one to three hours, even after ejaculation at this point my testicles would sometimes hurt for a few days making it hard to sleep on my side or sit down. My opinion was that the testicles had remained engorged for too long and were a tad sore like when you overwork a muscle at the gym, and then the fatigue goes away after time.
I do not know of a way to combat this, I can tell you after a few years your testicles just get more used to this mild form of abuse and you "bounce back" quicker.