I have found (and also heard it described as well) that when fishing a slinky, the bite is a very sharp tap or tap-tap or tap-tap-tap etc. etc. amongst the spongy feeling of a slinky along the bottom.

On the other hand, when fishing lead, the feeling of your lead ticking the bottom are very sharp tarps and when a fish picks up your offering, those sharp taps progress into spongey taps or pulls.

...but at the same time, this is coming from somewhen who has too many times over the years heard "Sparkey...SET the hook"