She may look serious, but in fact she loves masturbation.
Satomi, a beautiful wife with a neat face and glasses that suit her perfectly, has been buying up adult goods to relieve her sexual frustration.
The delivery man who delivers her the package somehow guesses what's inside, and his fantasies are aroused, resulting in an erection even while he's in the middle of delivering the package.
Witnessing this lewd physiological phenomenon, Satomi can't get the image of something bigger than her husband's out of her head...