M-shaped spread legs pose
Pornographic pose where the legs are spread wide with knees bent, forming an M shape. Used in adult content and related discussions.
In that video, the actress was striking an M-shaped spread legs pose.
Compound of Ｍ字 (emu-ji, 'letter M shape') and 開脚 (kaikyaku, 'spreading legs'). The term describes the visual resemblance to the letter M.