The bald guy. What the heck is he doing? He looks like a referee in a wresting match. Help? Totally useless.
Both of the cop's hands are occupied. Baldy should be punching the perp in the head continually. Eventually the perp will get sleepy.
More realistically, grab the perp by the back of the neck and use body weight to hold the head still. It distracts the perp, slows his body movement, and is unlikely to cause serious damage.
It won’t go viral for beating an arrestee, either.