Mina and Riho are two close married women. Mina's husband is a sports-loving dick-obsessed guy, while Riho's husband is a theoretical intellectual. They're both satisfied with their sex lives, but Riho suggests they swap husbands... And on the day of the swap, the four of them are at the peak of their sexual excitement and engage in a serious battle to see whose dick is hotter! "My husband's dick is..."