Ookami Shoujo to Kuro Ouji

Synopsis

It is Christmas break and Erika's classmates, Marin Tachibana and Aki Tezuka make a promise with her to share selfies of how they spent Christmas with their boyfriends. Erika tells Kyouya that they have to take a selfie as proof. Kyouya complies, however grudgingly so. Erika learns of Kyouya's dislike about Christmas and stresses out so much that she gets a stomachache. Kyouya takes her to the nearest restaurant before going to the pharmacy for stomach medication. When Kyouya "confesses" his feeling to her, Erika becomes ecstatic. However, Kyouya crushes those feelings by asking her how long he has to keep up this monkey business. Erika throws water at him and storms out. Kyouya sits in shock. When Christmas rolls around, Erika is still depress and sadden over Kyouya. Kyouya makes a surprise visit and gives her a "dog collar", a pretty golden heart necklace pendant. They take new selfies

(Source: Wikipedia)