The more analogue sounding scrub (as opposed to digital scrub, discussed previoulsy) might be described as sounding like audio tape being rocked back and forth over the play-head on a tape machine.
While continuing to press the K key, do any of the following:
i. Press and hold the J or the L key to scrub slowly either backward or forward.
ii. Tap the J or L key quickly/momentarily to scrub one frame at a time either backward or forward.
The multiple abilities of JKL are discussed in the Moving around: Methods and tips recipe in Appendix A, Additional Tips, Tricks, and Explanations.