![1girl ahoge alternate_costume bangs bell black_legwear blue_eyes blush boots breasts cake candle christmas christmas_cake christmas_ornaments christmas_tree cleavage food gift go-toubun_no_hanayome hair_ornament highres jingle_bell large_breasts long_hair long_sleeves looking_at_viewer nakano_itsuki neck_ribbon piyo_(pixiv_2308057) pom_pom_(clothes) red_hair ribbon sidelocks simple_background sitting smile snowman snowman_costume solo star star_hair_ornament sweater thighhighs uesugi_fuutarou white_background white_legwear zettai_ryouiki rating:s score:7 post #3778726](/cdn_image/preview/5b/93/5b930066e9da7eb146f3786f66201339.jpg)
Christmas cake, also urenokori (leftover, unsold items in a store's inventory), is the social myth or convention of women becoming unweddable once they hit a certain age. This is usually cited as 25. However, other cultures may have their own ages or terms for this, such as spinster or old maid.
Prime examples include Koigakubo Yuri, Kuroi Nanako, and Yamanaka Sawako. All are in their mid to late 20s, have no significant other, are fearful that they're past age, and typically become upset with their lack of a love life.
Images should include mature women with reference to either their age or the crippling, desperate loneliness and depression which consumes their existence.