Vanna measures how dealer delta changes when IV moves. When IV rises, negative vanna forces dealers to sell (headwind). When IV falls, it reverses.

Headwind = vanna works against the trend (dampens moves)  ·  Tailwind = vanna amplifies the trend

Charm measures how delta changes as time passes. As options decay, dealers must adjust hedges creating predictable directional flow, especially afternoon as 0DTE options approach expiry.

Sell Pressure = dealers sell as time passes  ·  Buy Pressure = dealers buy as time passes  ·  0DTE dominant = flow intensifies into close