hadaka apron 裸エプロン

In Japanese, hadaka epuron 裸エプロン, literally "naked apron," refers to a situation in which a girl is wearing nothing but an apron, which is a garment normally worn while cooking in the kitchen to protect your clothes from stains. There's no practical purpose in wearing it naked.

Character: Tamaki Kotatsu 環古達
Anime: En'en no Shouboutai 炎炎ノ消防隊 (Episode 10, Stitch)

• Examples
• References

Examples

The naked apron situation occurs in real-life pornography, drawn pornography (hentai), ecchi anime, and in fanservice. For reference, some examples:

Anime: Excel♥Saga, エクセル♥サーガ (Episode 26)

• Context: Watanabe Tooru 渡辺通 fantasizes that Hyatt ハイアット is his wife.
• okaerinasai anata
  おかえりなさいあなた
  [Welcome home, dear].
• oshokuji ni shimasu?
  soretomo ofuro?
  soretomo wa... ta... shi...?
  お食事にします？
  それともお風呂？
  それともわ・た・し？
  [What do you want to do?]
  Dinner? Bath? Or... me...?
  • An example of shinkon santaku 新婚三択, "newly-wed three choices."

Anime: Kotoura-san 琴浦さん (Episode 5)

• Context: Manabe Yoshihisa 真鍋義久 fantasizes that Kotoura Haruka 琴浦春香 is his wife, who provides him with three options of clothing.
• okaerinasai, anata
  おかえりなさい、あなた
  Welcome back, [dear].
  • anata
    あなた
    You. (second person pronoun.)
    Sometimes used by a wife to refer to her husband.
• kyou wa suku-mizu epuron ni suru?
  今日はスク水エプロンにする？
  Today, [will you choose] school-swimsuit-apron?
• soretomo buruma epuron ni suru?
  それともブルマエプロンにする？
  Or [will you choose] bloomers-apron?
• soretomo... hadaka epuron?
  それとも･･･裸エプロン？
  Or [is it]... naked apron?

Character: Ibaraki-douji 茨木童子
Anime: Onigiri 鬼斬 (Episode 13)

• Context: a completely random fanservice shot of Ibaraki-douji 茨木童子.
• oshokuji?
  ofuro?
  soretomo a... ta... shi...?
  お食事？
  おフロ？
  それともあ・た・し？
  Food? Bath? Or... me?
• tte nani kore?
  konna furifuri nugitai yo~!
  ってなにこれ？
  こんなフリフリ脱ぎたいよ～！
  [Wait], what is this?
  [I don't want to wear] something frilly like this!
  • nugu
    脱ぐ
    To undress. To remove clothes.

Since the average apron only covers the front of the body, a naked apron has a high chance of exposing:

• yoko-chichi
  横乳
  Sideboob.
  • See also: oppai おっぱい.

Character: Sandalphon サンダルフオン
Anime: Nanatsu no Bitoku 七つの美徳 (Episode 4)

Character: Sairenji Haruna 西連寺春菜
Anime: To LOVE-Ru Darkness, To LOVEるダークネス (6th OVA)

Other examples:

Left: Stunk スタンク
Right: Demia デミア
Anime: Ishuzoku Reviewers, 異種族レビュアーズ (Episode 10)

Character: Erza Scarlet エルザ・スカーレット
Anime: Fairy Tail, フェアリーテイル (2014) (Episode 28)

Character: "Kobold's wife," Koboruto no okusan コボルトの奥さん
Anime: Hataage! Kemono Michi 旗揚!！けものみち (Episode 3)

• Does this even count?

Anime: Anime de Wakaru Shinryounaika アニメで分かる心療内科 (Episode 19)

• Context: an episode about yuusei hannou 優勢反応, "dominant response," a concept in social psychology.
• osouji shinakya!
  おそうじしなきゃ！
  [I] got to clean [the house]!
• demo mendokusai
  でもめんどくさ～い
  But [that] is a pain.

References

• 裸エプロン - dic.pixiv.net, accessed 2020-02-26.