A reference to a scene from Dragon Ball where Yamcha was crumpled up in a crater after being caught in a Saibaman's self-destruction attack. The pose has become memetic as a way of expressing comically defeated characters in doujins.
The pose itself involves the character laying down on their right side, face pointed away and viewed feet-first, and with limbs curled halfway into a fetal position. The character in the pose is usually in a smoking crater, even if whatever put them in the Yamcha pose wasn't even an explosive.
