Yoshi had been born with a serious genetic disorder. Once he hit puberty he began to produce semen, and never stopped. If he didn't expel the fluid from his body it would gather in his balls, which fortunately swelled beyond normal human limits though it was of course dangerous to do that indefinitely. But in the modern day he never had to worry about much with toys and videos aplenty, though keeping girlfriends was hard work. Apparently guilt tripping women into giving you a nurse handjob ruined relationships.
His buddy Koma had no such issues and was getting married. He even picked Yoshi for his best man. His fiance Mika however did not like Yoshi because she thought he was just a pervert that always smelled like cum. She didn't know the legitimate medical issue because it's awkward to explain so she just treated him shitty and Koma went out of his way to make up for it later. Koma and Mika were set to have an island wedding and decided to do a pre-honeymoon with family and friends enjoying the beach atmosphere.
This was partly cost based as it was incredibly cheap. Everyone involved was too dumb to check why it was cheap, and they had to suffer for a week long island storm. Endless movies and board games and complaining uncles. Worst of all for Yoshi in an act of petty spite Mika had put her mother sharing the room with Yoshi and was constantly nagging him and ensuring he didn't have time to jack off. Nor was there anywhere to sneak off to as the small hotel was basically unleavable and he did have a few duties as best man to keep himself occupied.
So after a week of this torture the evening before the wedding Yoshi had to go talk to Mika. All he wanted was for Mika to keep her mom busy while Yoshi relieved himself. At this point his ball bag was nearly the size of a basketball and he had to waddle through the hallway. Koma had seen him and felt incredibly bad about causing the situation. He was behind a curtain at the moment so that Mika could try on her bridal outfit. Mika put on a polite face, even though Yoshi reeked of cum. Her mouth salivated at it, especially since this whole event had been a disaster and she hadn't been able to sleep with her beloved Koma at all.
"I have to explain my problem." Yoshi said loudly, so Koma would hear. Being a shy person around the subject Koma made his excuse to leave, which was taken very differently from how he intended.
"Sure pal, do whatever it takes." Koma said hurriedly as he made his exit. He very much didn't like thinking about his best friend's swollen balls.
But Mika didn't understand what was going on. Sure Yoshi was in pain, but was she expected to help him somehow? And what dumb prank involved shoving a volleyball in his sweatpants. Mika sighed and rolled her eyes as she gave Yoshi her undivided attention. He appreciated the view and cursed Komas good luck. She had natural 36B tits, a clean shoulder length haircut, perfect skin, in many ways the perfect japanese wife. Currently wearing a thin white shirt with the bra showing through, and was touching up her bride gown bottom to be perfect.
She couldn't believe her ears at first, but absolutely couldn't believe her eyes when his pants went down. His hands modestly cupped around his cock but nothing could hide the monstrously swollen scrotum. Mika suddenly took everything very seriously and was worried, desperately, about Yoshi's health. She wasn't evil but another top priority that came to mind was if his balls exploded the wedding would likely be canceled.
Yoshi felt awful, his guts twisting as he stammered out an explanation of why he couldn't handle this himself. His guilt increased as he saw Mika's nose keep twitching at the smell of his gallon of cum waiting for expulsion. Mika nodded along for a minute then shushed him.
