If you don’t know what it means, try and search for some MachineDrum, MonoMachine tutorials and you’ll see what the idea is about in a visual/audio context.
But wouldn’t it be possible to implement a similar feature into Renoise ?
E.g. enter PL-mode the down/up-arrow keys selects the next step with an entry, the mouse movements, buttons, scroll-wheel etc. can change an assignable parameter.
E.g. you have a simple 4/4 basedrum track, in PL-mode one hit of the up/down-keys will select the next hit of the BD, once selected the mouse movements would adjust the volume, pan etc. whatever you’ve assigned to the mouse movements.
So it kind of acts like an imediate automation input.