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