Twisted Knee Collapse

A character, usually female, who collapses from exhaustion or dejection sometimes lands on their knees, with the lower legs splayed out sideways while the thighs remain together. This is difficult to do for all but the most limber of people in real life, and even then it's not very comfortable.

This usually occurs when the character's body is facing the camera instead of in profile, ignoring three-dimensional perspective in favor of looking cute.

The obvious reason for this is to Preserve The Dreaded G Rating - far more commonly, the female suffers Magic Skirt failure due to landing in the far more realistic and comfortable position of sitting down with her thighs spread, Leading To The Beloved Panty Shot. Open or closed, the sitting position is called pettanko due to the legs visually flattening out against the ground. It is independent of the sitter's chest curvature.

Anime and Manga

 * Before the Time Skip, Sakura from Naruto did this a lot.
 * Often done by Nyu in Elfen Lied.
 * Ichigo does this in Tokyo Mew Mew when she's being chased by Kisshu her Stalker With a Crush.
 * As does Melfina in Outlaw Star.
 * Winry from Fullmetal Alchemist does this on occasion. Specially when
 * Bulma of Dragonball does this every now and then.
 * Mai-HiME: In episode 24, Dark Magical Girl Nao Yuuki goes into this position after
 * In Episode 15, Yukino does this after she thinks Mai has been killed by a direct hit from Artemis.
 * In a more comedic example, this happens in Episode 9 when Natsuki notices that the car that stops for her while she is posing has Youko, Midori, Reito and Shizuru in it.
 * In Strawberry Panic, Yaya sits like this after.
 * This is the standard sitting position of Kotomi Ichinose from Clannad. Okazaki lampshades how uncomfortable it must be.
 * Sailor Moon. Usagi. Often combined with Ocular Gushers or Sparkling Stream of Tears.
 * The main heroine from Revolutionary Girl Utena Utena fell victim to this with a sickening sneaker squeak and the echoing sound of her knees hitting the floor as she was brought down with the aid of a sword being run through her back, while in the one armed embrace of her princess, who was using her other hand to push said sword through her.
 * Fate does this in the first chapter of Magical Girl Lyrical Nanoha ViVid after witnessing Vivio's Transformation Sequence. Poor Fate wasn't quite expecting to see Vivio since Nanoha kinda forget to mention that little detail to her.
 * Female Ranma in Ranma 1/2 collapses on her rump, knees and thighs together and legs splayed out, when Kunou first declares his budding love for her with a bouquet of roses. Especially strange since Ranma is typically very masculine and her reaction wasn't just straight out of a shojo manga, she was actually shocked into stereotypically girlish submission (instead of being outraged into beating the crap out of Kunou.)
 * To be fair, this was the first time in his life something like this had happened, and resulted in the first of Ranma's nightmares about men hitting on him. This was probably the incident that hammered home how much his Gender Bender curse was going to mess with his life.
 * Happens again to Ranma-chan after Cologne reveals she's used the "Full Body Cat's Tongue" to hit Ranma's Pressure Points and trap him in his female form, in an effort to force him to agree to his Accidental Marriage to Shampoo.
 * Miaka from Fushigi Yuugi.
 * Honda Tohru from Fruits Basket has been known to do this on occasion, usually apologizing for something.
 * Yoshino does this in the second Digimon Savers opening. It looks even more awkward and less comfortable than normal through its clear fanservicey intent.
 * Risa does this in episode 5 of D.N.Angel after becoming exhausted from running.

Video Games

 * In Osu Tatakae Ouendan and Elite Beat Agents, failing on the highest difficulty will cause the Cheer Girls or Elite Beat Divas to slump into this position on the bottom screen while the target's life falls apart on the top screen.
 * Kairi and Namine in Kingdom Hearts.
 * This is the pose that  takes in Ace Attorney.
 * In Rock Band 3, sometimes your guitarist will slide/dive into this position during a solo. (I'm not sure if the move was in the previous games.)
 * More than one already defeated character in the early King of Fighters games is seen in this position in the background, i.e. Athena Asamiya.
 * Final Fantasy XIII-2: Serah Farron collapses this way in pure grief and hopelessness when
 * She also falls into this position

Western Animation

 * Teen Titans: Raven did this a few times in the episode "Birthmark".
 * Starfire did this a lot.
 * To say nothing of Kim Possible.