Clamp transform.rotation?

I know that it's near impossible to clamp a quaternion. But how would I put a clamp in t$$anonymous$$s code for the transform.rotation? Any method is fine. I put a comment "CLAMP TRANSFORM.ROTATION" where I was trying to put it. Thanks in advance if anyone helps.

                     Quaternion OriginalRot = transform.rotation;
                     transform.LookAt(otherObj.transform);
                     Debug.Log("Looking At Other.");
                     Quaternion NewRot = transform.rotation;
                     transform.rotation = OriginalRot;
                     transform.rotation = Quaternion.Lerp(transform.rotation, NewRot, (speed * Time.deltaTime) * 5);
                     //CLAMP TRANSFORM.ROTATION