How to do continuous movement on a parameter

[clever moat]

example: rurumi's pigtails wagging only when she smiles
https://youtube.com/shorts/WH2Q1tUxRtU?feature=share

[maiden badge]

the motion will want to be bound to two paramenters, 1, mouth smile, and 2, a repeating animation parameter,

then set mouth smile =1 and right eh wagging loop to the animation parameter

Lastly you will either create an idle animation containing the rigging for the animation parameter, or make a physics clock like this https://www.youtube.com/watch?v=Jl-i7f4LYNY

because you only rigged the animation parameter for when the mouth was smiling, the animation wont play when the mouth is not

[clever moat]

if I make it an idle animation, do I then apply it using the live2d viewer?