What Is the Red “S-Line” Trend on Instagram and TikTok?

Download Article

Here’s how a K-drama led to red lines floating above people’s heads

Co-authored by Glenn Carreau Reviewed by Candace Gasper

Last Updated: August 27, 2025 Fact Checked

Download Article

What is the red line trend?

|

Origins of the Trend

|

S-Line Trend Memes

|

Does body count matter?

|

What is S-Line about?

|

Video

Have you been scrolling Instagram, X (Twitter), or TikTok, only to be totally puzzled by all the posts with weird, red lines drawn on them? Don’t worry, we can explain everything! The S-Line trend—featuring red lines floating above people’s heads—is a reference to the Korean drama series S-Line, in which the red lines indicate the number of sexual relationships a person has had (and with whom). While the show is a dramatic thriller, the S-Line trend online is much more playful, with lots of memes and jokes going viral. Keep scrolling to learn all about this online trend and its meaning!

A Quick Overview of the S-Line Trend

The S-Line trend refers to social media posts with red lines drawn on them, based on the premise of the Korean drama series S-Line. In the show, red lines represent connections between people involved sexually. In memes, people use red lines to joke about the show or playfully draw similar connections in their lives.

Section 1 of 5:

What is the red line trend on social media?

Download Article

1
The red line trend is based on the Korean drama series S-Line. The TV series began airing in July 2025 on the streaming service Wavve—and memes based on the show (and its premise) began flooding social media! In the show, a woman can see red threads connecting people who’ve been sexually intimate.^{[1]
X
Research source} On social media, the red lines you might see in various videos and posts are a reference to the show.
- While red lines in the show indicate a sexual relationship between people, not all memes are sexual as well.
- Some people do use red lines in their posts to indicate their relationships with people, while others use red lines to make jokes about their intense desires or connections to other things (like a favorite food, for example).
2
Red lines represent sexual bonds and the shame associated with them. In the show, the red lines connecting people contain layers of symbolism; they represent sexual connections, but on a deeper level, they’re also symbolic of the shame people are made to feel about their relationships, as well as themes of privacy and the social pressure to be discreet about one’s relationships.
- As we’ve mentioned, not every social media post about red lines or S-Line has the same layers of symbolism.
- Nonetheless, the red lines people are using for their posts are very much based on the heavily meaningful lines featured in the show!

Section 2 of 5:

How did the S-Line trend start online?

Download Article

The first red line post surfaced in June 2025. That’s right, posts came in hot off the press before the show itself actually aired! That’s because X (Twitter) users began posting about S-Line’s trailer first; the initial viral post came on June 12, from user @0dan79, and in the next few days, more memes and edits followed. For instance, on June 21, X user @luckybaak posted a picture of two characters from Gintama (an anime and manga) with red lines connecting them.^{[2]
X
Research source}
- By July, the meme format had really begun to take off, with many more videos and viral posts shared online. We’ll cover more examples of S-Line memes below.

Section 3 of 5:

The Internet’s Many “S-Line” Trend Memes

Download Article

1
The red line meme has been used to show real and fantasized connections. Some people use the S-Line trend to show off their favorite K-pop idols, Korean actors, or other celebrities—drawing red lines linking themselves to their celebrity crushes. Other people actually do use the S-Line trend to draw red lines between themselves and people they’re dating (sometimes in seriousness, sometimes to tell a joke).
- For instance, TikTok user @thetriotbros posted a video with the caption “REAL LIFE S LINE 🤣,” with the people in the video chatting and having a conversation despite being connected by red lines.
- TikTok user @dramasol used the meme to make fun of Lee Soo Hyuk’s character, posting a video with clips from the show featuring random characters with the caption “Others S line” followed by his character and the caption “This man 💀”.
- Instagram user @vivendodedoramas_ made a post with a silhouette (representing themself) with red lines connecting to a while chart of different K-pop idols and actors.
2
Some people use the S-Line trend to joke about things they really want. Maybe you wish you were rolling in money or able to treat yourself to all the finer things—we all have those wishes sometimes! Well, people on social media are using the S-Line trend to draw red lines between themselves and all the things they wish they were connected to in life.
- On Instagram, @memesticguy made a post with the caption “The only S-line I want” and red lines connecting things like a credit card, fine clothing, a fancy car—and, naturally, Ryan Gosling.
3
The S-Line trend also pokes fun at life’s more unfortunate connections. That’s right: plenty of other social media users have taken the S-Line trend and turned it into a joke about all the problems connected to them in real life—things that would definitely show up if you could see little red lines indicating everything a person was feeling anxious about!
- For example, X (Twitter) user @wtffrio posted a meme with a cartoon figure connected by red lines to things like “mental health,” “financial crisis,” “responsibility,” and “99+ other issue” in a post that gained over 119,000 likes.

Section 4 of 5:

Does someone’s S-Line count (body count) matter?

Download Article

Body count shouldn’t matter; it isn’t a reflection on someone’s character. The original meaning of the red lines was, of course, referring to the number of people someone had slept with—and some feel all the jokes have gotten a little insensitive. And they have a point: after all, a person’s “body count” (referring to the number of sexual relationships they’ve had) shouldn’t be something to make fun of them over.^{[3]
X
Research source}
- Many people have differing opinions on “body counts” and whether they’re something to be admired, judged, or kept discreet.
- So long as every relationship or encounter is approached with respect, consent, and open communication, it shouldn’t matter how many connections a person has had in their past.
- At the end of the day, a person’s “body count” is their business, and it doesn’t determine their value or ability to love others. People approach intimacy differently, and that’s okay!

Section 5 of 5:

What is S-Line about?

Download Article

S-Line creates a social commentary on sex and how society perceives it. It follows Shin Hyun-Heup (played by Arin), a girl with the ability to see glowing red threads connecting people who’ve been sexually intimate, as well as Kyu-Jin (Lee Da-Hee) as a high school teacher hiding strange secrets. A pair of glasses is created, allowing other people to see the same lines Hyun-Heup sees, throwing society into chaos.^{[4]
X
Research source}
- The show’s other main character, free-spirited detective Han Ji-Wook (Lee Soo-Hyuk), resolves to find the people responsible for the glasses.
- The show itself is based on Little Bee’s webtoon—also called S-Line—which was a hit among its readers.