Jewelry is small and hard to see, and a bit beyond the typical high-schooler's budget. So how's a TV show to demonstrate that Bob and Alice are a couple? Well, making mad passionate sex would probably do it, but would probably get the show booted from prime time. Also, the FCC frowns upon even simulated underage sex. So instead, Alice wears Bob's jacket. If Bob's some kind of athlete, expect it to be his letterman jacket. This is Truth in Television, and not limited to jackets. Women like stealing men's clothing. A little research indicates that the reason girls do this is fourfold. First, they're big and comfy. Second, it marks both of them as taken. Third, it's like a day-long hug. Finally, it smells like him. This can be more than just an "I like this and I like you" gesture. It can be a symbol of commitment. Sometimes it's a class ring, or a necklace, or a favorite hat. The point is that one partner is wearing something that until then was always seen on the other, so that the world knows they're a couple. And it need not only be women wearing something of their men's collection. A man is less likely to wear his girlfriend's clothing, but a token is often passed in that direction, as in Chivalric Romance when a knight takes a lady's scarf with him into battle. Related to You Must Be Cold, which is a one-time romantic gesture (often as part of a Ship Tease). This is a long term appropriation of clothing to demonstrate a relationship. Also related to Sexy Shirt Switch, where she appropriates other articles of clothing after sex. These are all signs of intimacy. Sexy Shirt Switch is sexual intimacy, Her Boyfriends Jacket is emotional intimacy (slash ownership).
- There's a style of clothing in fashion known as "boyfriend clothing". It's clothing that was designed for men and redesigned for women. It looks like typical men's fashion, but with a looser fit more comfortable for women. From the other wiki, "The origin of boyfriend fashion is literally borrowing and wearing a boyfriend's clothes—his distressed jeans, his band tees, his dress shirts, his blazers, his cardigan. The trend expanded in 2009 when actress Katie Holmes was spotted in public wearing Tom Cruise's slouchy jeans after a Broadway rehearsal; other celebrities such as Reese Witherspoon, Rachel Bilson, Sarah Jessica Parker, and others began to follow the trend. From there, many brands such as Gap, Forever 21 and H&M began to create boyfriend fashion products or men's-inspired fashion."
- In Last Exile after Claus and Tatiana crash land in the desert, at one point he offers her some spare coveralls as a change of clothes. When they get back to the Silvana, Claus' old friend Lavie sees Tatiana wearing his clothes and she begins to fear this is happening.
- At the beginning of Episode 17 of Digimon Frontier, Koji offers his jacket to Zoe for her to wear when she's feeling cold, which leaves JP feeling rather jealous.
- In the X-Wing Series, the first indication of a relationship starting between Corran and Mirax is her walking into the fighter bay wearing his flight jacket. She even pulls it closer around her when she notices one of the female pilots glaring at her.
- Discworld Why And Were has a scene where Assassin Johanna dons Wizard Ponder Stibbons' wizarding robes. Partly because they're warm, comfortable and smell slightly of Ponder. (a big plus in the early stages of a relationship). But mainly because she'd otherwise have had to answer the door naked.
- The magnificently funny Ranma ˝ fanfic Crossed Wires spoofs this trope when Ranma in girl mode has to borrow Ryouga's clothes, including his distinctive shirt, and everyone immediately assumes this trope is now in play. Hilarity Ensues.
- Shelly in Sin City wears Dwight's shirt when Jackie Boy arrives at her apartment. He is not amused.
- In Jarhead, the girlfriend of one of the marines keeps sending him sexy photos of her wearing his uniform jackets (and nothing else). One of the other marines eventually asks if she has any clothing of her own.
- Cyberthriller The Net has Angela Bennett wrap herself with Jack Devlin's sport coat while aboard his boat. When she finds a gun with a silencer in one pocket, she begins to suspect that Jack intends to murder her.
- Cherry in Planet Terror wears El Ray's leather jacket, much to his chargrin since she left him and he was searching for it for months.
- In The Dark Side of Nowhere, there's a gender reversal of this. Girls wearing their boyfriend's letter-jacket to signify that they are together is a custom in their high-school, but where protagonist Jason gets together with his athletic tomboy love interest, he wears her letter-jacket.
- In his book Couplehood Paul Reiser complains about this practice (Link!)...
And of course, later, it's freezing, and she's huddled in my jacket, and I, who knew to bring a jacket, am wearing no jacket. And the kicker is: It's not like my jacket looks so good on her anyway. It certainly looks worse than whatever jacket of her own she would have put on.
- Amy Pond from Doctor Who disconsolate after the death of the Doctor in the Wedding of River Song, is shown consoling herself by drinking wine on her patio, wearing the letterman jacket Rory was sporting in Let's Kill Hitler.
- Buffy the Vampire Slayer:
- Angel gives Buffy his leather jacket in the fourth episode, Teacher's Pet, she wears it for the rest of the first season, albeit with the sleeves rolled up. They're not a couple yet, but when he says, at the end of the episode, that "it looks better on you", she knows she's fallen for him.
- Tara wears Willow's sweater in the fourth season episode "New Moon Rising", which precipitates the episode's trouble.
- Discussed and subverted in the second season. Finn and Rachel think that Sam is dating Kurt after they see him wearing Kurt's jacket, specifically citing the common practice among girls of wearing their boyfriend's jackets. It later turns out that Sam's dad lost his job, with the result of the Evans family becoming so poor that they're staying in a hotel room. The jacket in question was part of a handout package consisting of Kurt's old clothes given specifically with the intent of helping out Sam's family.
- In the fourth season, a Betty and Veronica Love Triangle is established between Marley, Kitty, and Jake when Marley spends a few days wearing Jake's coat (from a You Must Be Cold moment) and Kitty demands it as this trope when she and Jake start dating (though he doesn't like labels).
- An episode of My Family involves Janey being given her boyfriend's jacket and taking a liking to it so much she tries to avoid giving it back even after dumping him. Eventually he tricks her into giving it back, though she manages to coax it out of him by dating him again.
- This becomes a plot device in an episode of Leave It to Beaver, in which Mary-Ellen Rogers wants to impress her friends, and charms Wally into letting her wear his letterman sweater.
- In "The Little Kicks" episode of Seinfeld, Anna returns to work at the J. Peterman Catalog at one point, wearing George's Yankees jacket, after Elaine warned her to stay away from him on the grounds that he's "a bad seed".
- Blue Mary in Fatal Fury. The boyfriend in question is deceased, though how was not elaborated on by much.
- In the fourth season of The Guild, after Codex and Fawkes sleep together and he accidentally leaves his jacket at her place, she assumes they're totally dating and wears said jacket on what she thinks is a date... and he sends someone else to pick it up.
- Gunnerkrigg Court: In Chapter 14 Kat can be seen wearing the T-shirt of her brief love interest, Alistair, who left her his personal belongings after he had to turn into a bird and leave.
- In Questionable Content, Hannelore and Sven go on a fake date (because she never has), a the end of which she looks 'absolutely adorable wearing his hoodie against the cold.
- A memorable episode of Pepper Ann had the title character start wearing Milo's ever-present hat so it would look like they were dating, and to cope Milo started wearing continuously more ridiculous hats as the episode progressed.
- During the brief time they were dating in As Told by Ginger, Ginger did wear Darrin's jacket.
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