It started with Yosh, around age 7, the little green dino duck is still in diapers and having accidents, and ended up peeing his diaper.

Daddy ducky took him to go get changed, undid his diaper, and of course saw how cute and itsy bitsy Yosh is down there, like daddy himself! But his dad wasn't prepared with a diaper or anything, and tried covering Yosh's lil winky tip with his feathered wing while he looked. Of course, that tickled Yosh, and made him pee again! The initial surprise made Mr. O'Ducky move his wing so it wouldn't get peed on - but Yosh's lil penis was pointed right at him. He tried covering himself with his wings, but his top half got covered pretty quick! He then tried using his wing in front of Yosh's peepee to stop it, but that just splashed back on Yosh and, they both ended up a bit too covered in pee and needed a bath.

So, they both got fully undressed and got in the tub! Yosh first, with his daddy a bit embarrassed to be naked and coming in after, walking toward his son fully nude with his daddy dinky bouncing along between his legs. Yosh could see it all! Sharing a bath'd be fun and normal, but with Yosh being a lil older, he'd bounce and splash around more, and his tail'd slide or rub against daddy ducky's privates. The daddy'd try to keep Yosh a lil distance from them, practicing yoshial distance, but after a few more bumps of his privates, Daddy Duck decides he'll just stand in the tub. Even if that means Yosh just has to look up to see some shrunken male birdy bits!

Of course, that's just in time for Yosh's younger yellow-feathered sister, Winry, to peek in and see what's going on. The young duckling sees her dad's penis and parts right in front of her! And can even note how they're a little similar to Yosh's. Same size and everything, despite them being father and son... But, she might not have to imagine long, since Yosh'd stand up too, and tell Winry to close the door and get out. But, that'd give her a view of both her naked dad and brother - and easily comparing how cute and small their striped winkies are together. Yosh's mom also popped through the cracked open door as she got Winry, so the two boys could have some privacy, and while doing so, she got to see them both too. Now both girls of the family saw both the males standing up, wet and naked, genitals exposed to the mother and daughter. After that they'd both cover up and get back to bathing, completely embarrassed together.

The bath would end with Yosh and his dad drying off together, and both of them diapering up! And their mom helped with that part - having both of them lay down naked on the family bed, have diapers slipped under them, their little winkies in the air, as mama yoshi powders their fronts, rubs em in a little. She then diapers Yosh and his dad! Yosh first (he probably needs diapers the most) which'd make it easier for Yosh to watch his dad get diapered, nude and submissive right in front of mommy, a little to his own embarrassment. But at the end of a weird, fun lil father-son time for Yosh and his ducky dad, they were both finally clean, covered, and diapered for the day!