This can be done by morphing in mid-air, then quickly turning on Spring Ball while still climbing upwards, and then jumping again.
This is often done most easily by buffering the Spring Ball jump: while unpausing after turning on Spring Ball, press and hold jump starting anytime after the pause menu has finished fading out (i.e. while the screen is black).
This is often combined with a crouch jump to gain a bit more height.
See also: Tech Page