As Goku went to move up to the balls of her feet, he found them too high for him to reach normally. With no other option, he flies higher to better reach them. Unfortunately, doing so puts him closer to her toes, putting his face right at the source of the smell. He crinkled his nose as he continued rubbing. The flesh up here was more firm, but that only meant it made his hands slip around from sweat easier, forcing him to put more of his back into rubbing.
Meanwhile, Chi-Chi was in heaven. She loved the feel of his little hands rubbing themselves across her aching feet. She's wanted this level of pampering and attention from Goku for years now, but never could get him to do it with how quickly he could outrun her. But now at this soze, with this power, she could catch him even at his top speed, so she calls the shots now.
"This feels so nice Goku. Good to see you finally taking the time to please your wife after all these years. Maybe after dinner, you can clean my feet for me." She says with a smirk.
Goku cringed at the offer. "And why.. hngh.. should I do that?" The saiyan asked while doing one more big push on the ball. After the question, a big drop of foot sweat fell on Goku's head, drenching him. With the balls done, Goku moved up and began to rub between the toes. Meanwhile, Gohan was more than half done the fish, meaning Goku needed to speed up now.
"Because Goku, from now on, I'm not going to wash them myself anymore." She tells him. "And I'm gonna be asking for foot rubs like this before every meal. So if you ever want to eat my cooking again, you'll be rubbing them every day, and if you don't want the smell to get worse and worse, then I suggest you agree to clean them after dinner."
Goku went cold at the idea of this smell getting any worse. "Okay, okay! I'll do it." He says quickly. Finally, Goku finishes the last toe. "There. How's that?"
"Not bad. Not perfect, but I'm sure you'll get better with practice." She says with another toe wiggle. "Okay, run along then and enjoy your food." With his wife's approval, Goku finally turned away from the rank foot to that succulent fish to see...