The flexibility and support of a sex doll largely depend on its joint design, which influences both realism and ease of movement. Different dolls incorporate a variety of joint systems, from simple hinges to complex, anatomically accurate articulations. Basic models often use fixed joints or limited movement points, offering stability but less flexibility, ideal for static display or limited posing. More advanced dolls feature multi-axis joints that mimic human movement, allowing for a wide range of poses with natural support. These joints are typically constructed using internal metal skeletons or reinforced frameworks, providing stability while enabling smooth, lifelike motion. The supportiveness of joints also varies based on their placement and construction. For example, shoulder and hip joints with ball-and-socket mechanisms offer greater rotational movement, while hinge joints in elbows and knees allow bending but limit rotation. High-quality dolls often incorporate adjustable joints with locking mechanisms, enabling users to set preferred poses securely. The choice between different joint types depends on user preferences—whether prioritizing realistic posing, stability during use, or ease of movement. Ultimately, the best sex dolls combine flexible joint systems with sturdy support structures, allowing for natural positioning without compromising durability or comfort.