twiddle

US /ˈtwɪd.əl/
UK /ˈtwɪd.əl/
1.

lảng vảng

to move something repeatedly between your fingers, especially without any purpose:

:
She was twiddling (with) a pencil/her hair.
1.

lảng vảng

an act of turning something with the fingers:

:
At the twiddle of a knob the operators can focus on a tiny amount of airspace or scan the whole area.