The dynamic realism of the life size sex doll depends on the elastic modulus of the material. Silicone flat chested sex dolls have made significant breakthroughs in motion simulation. The bionic chest structure developed by MIT uses the viscoelasticity of silicone to simulate the millimeter-level fluctuations of the chest during breathing. The low fat mass characteristics of the flat-chested area require more precise mechanical feedback - the damping coefficient of silicone (0.12) reduces the tactile feedback delay to 8ms, compared with 23ms of TPE material, greatly improving the realism of dynamic interaction.