Kuroko's dog, Nigou (AKA #2), is jealous and thinks the Dekabutsu (the Big One, AKA Kagami) is stupid and unfair and all around bad. The first part of the story is him trying to find ways to discredit Kagami in Kuroko's eyes. One of these involves finding Alex's underwear, which she left behind, in the guest room. To atone for this sin, Kuroko wants Kagami crossdress in Alex's underwear. Kagami eventually surrenders when Kuroko does those whimper-whimper puppy-dog eyes and sexy shenanigans ensue, with Kuroko topping Kagami in the end.

High quality scans by ansibs.

Information: http://doujinshi.mugimugi.org/book/540091/