Suboccipital release with tennis balls ("Suboccipital release" Suboccipital self mobilization, with ball, supine)

Place two tennis balls side by side in a sock.
The sock provides padding.
Lie back, placing the tennis balls just below the base of your skull.
The tennis balls will apply pressure directly into the suboccipital muscles of the neck.
These are the headache muscles.
It's important to use tennis balls and not a hard ball, such as a golf ball.
Hold the position on a tender spot.