The key word is risk. Either the risk ends up happening or it doesn't. I.e. either the stock market tanks during your first several years of retirement or it doesn't. You don't need to cash in your hedge if the risk doesn't happen.
The damage occurs when you sell stocks at relatively depressed prices during a multi-year bear market like the 1930s, 1970s, 2000-2003, or 2008-2009. When stocks come back, you are left holding fewer shares because you sold them for living expenses. Thus, due to the math of gains and losses, you recover much less than if you had held. E.g. You start retirement with 10,000 shares of an index ETF priced at $100 each and as luck would have it the market drops 40%. Now to obtain your $40,000/year you need to sell 667 shares instead of 400. When the market fully recovers the next year, you have 267 fewer shares than you would have had if that dip never occurred. The market recovered completely but you are still down $26,700 compared to a hypothetical world where markets had been flat! Multiply that by a few years and you have a big SORR.
Your cash/bond allocation is there to reduce the number of shares you have to sell at cheap prices during a major correction as described above. E.g. had you funded that year out of cash and bonds, you would have used up $40k worth of cash and bonds that would have been worth about $40k after the correction, instead of 667 shares that would have been worth $66,700 after the correction.
But you'd only need to tap the cash/bond allocation if a big correction / bear market actually occurrs. Otherwise, you should stick to an AA. Recommended steps:
1) Set target asset allocations for each of the next 10 years. Withdraws should be proportional.
2) Write an IPS describing under what circumstances you will withdraw more from cash/bonds instead of proportionally from each part of your target AA as you'd normally do. This could be as simple as "withdraws shall be 100% from cash/bonds any time the S&P500 is 30% lower than its all-time high" or it could be some kind of step ladder or mathematical function that slowly increases the percentage of the draw that comes from bonds/cash. E.g. "When the stock market is more than 15% below its all-time-high, increase the percentage of monthly withdraws that come from cash/bonds by 3.5X the percentage the stock market is below its all-time high, up to 100%." Bear in mind, this rule could be in use for years. Pencil out the scenarios.
3) Stick to it no matter what. NO. MATTER. WHAT. Asteroid? Stick to it. Another pandemic? Stick to it. Nuclear war? Stick to it. Trump re-elected in 2024? Stick to it. Zombie apocalypse. Stick to it, could be the original George Romero scenario where it gets under control quickly and we just mistreat the remaining zombies for fun.