Smudge Brush Tool

The following settings can be adjusted from the context toolbar:

Width—the brush (stroke) size in pixels. Type directly in the text box or drag the pop-up slider to set the value.
Flow—how fast the brush effect is applied (1% is very slow, 100% is immediate). Type directly in the text box or drag the pop-up slider to set the value.
Force pressure to control size—Click to control brush size with pressure if using a pressure-sensitive device. This overrides brush defaults.
Strength—defines the extent to the smudging. Type directly in the text box or drag the pop-up slider to set the value.
Symmetry—when set to greater than 0, repeats the brush stroke around a number of axes (defined by the symmetry value). The centre axis point can be repositioned by click-dragging it.
Mirror—with symmetry enabled, causes brush strokes to be mirrored along the X and Y axis.
Lock—when checked, prevents the symmetry line from being moved.