For weapon retention, I instruct my officers to place both of their hands in a “C” clamp-style grab, one hand in the rear of the weapon holster under the pistol grip, and one in front of the holster. Then lower their center of gravity and use their elbows as striking weapons by moving back and forth from the waist forcefully.
This movement will enable the officer to get the offender off of them, and then allow the officer to create some distance to follow up with other options. This is easily practiced with striking bags for the elbow strikes, and with fellow officers for the physical retention technique.