Picking up a soft ball using dual arm

I am trying to pick a soft ball using two arms and then throw it. I am using a soft ball because I want to be able to throw the ball even when it is slightly crushed by the fingers. But when I try to run it using gazebo, the ball jumps around on contact. I tried making the object soft using different values of `kp, kd, soft_cfm and soft_erp` with no success. Any suggestions on how I can achieve this. `ball.sdf` false0.250.001690.001690.001690000.130.13 `finger.sdf` 0 0 0 0 1.5707963267948966 00 0 0 1.5707963267948966 0 0model://finger/finger.stl0 0 0 0 0 0  Just before the contact between the fingers and the ball  Collision model