Liquify Brush Size

When you are using any of the liquify tools (Warp, Twirl, etc.) and your brush is the wrong size, press- and-hold the Option key (PC: Alt key), and drag to change the size. Drag outwards to make the size larger, drag inwards to make it smaller. (Note: Using Option/Alt alone will alter the brush size non- proportionally. If you want to keep the brush as a perfect circle but change its size, use Option-Shift [PC: Alt-Shift].)