To produce transverse waves, the student should wiggle his end
of the spring either left-right, or up-down, or upper-left/lower right,
or lower-left/upper right, etc. ... back and forth along any line that's
perpendicular to the spring itself.
I think he can create a transverse wave and a longitudinal wave
both at the same time. f his wiggles have any component at all
that's parallel to the spring, then he'll put a longitudinal wave into
the spring. If he only does push-pull-push-pull, then the wave
will be purely longitudinal, with no transverse wave at all.