Click and drag to draw with 3-point perspective. Lines will only go towards your three vanishing points, or aligned with the "horizon" defined by two of the vanishing points.
This tool is operated in a freehand fashion.
See also: 1-Point Draw, 1-Point Select, 2-Point Draw, 2-Point Select, 3-Point Select, & Perspective.
Tux Paint 0.9.32