"Shall we join them?" 
Reiji, accompanied by his wife Kanade and their close friends Kosuke and Asuka, had visited the inn for vacation. On the first day, during dinner, a heated argument broke out between the two couples, and Asuka dragged Reiji away to her room. But from inside, he could hear his wife Kanade's restless sighs... (Source: Coolmic)
 
Note: The complete edition with explicit scenes was distributed web via Comic Festa Anime Zone. The on-air version was broadcasted on Tokyo MX and BS11.

Married Couple Swap