Another variation on this type of shot is to orient the cue
about 45 degrees relative to a normal straight on stroke.
Then move the cue along its axis across the cueball just
brushing the cue ball. A small drawing viewed from ABOVE
is attached below, hope it illustrates the method OK.
I used this in an 8 ball tourney in Las Vegas once and my
opponent's jaw dropped to the floor. It was witnessed by
a qualified referee and he called a good hit. Went on to
win the tourney.