Selling deep in the money calls is a great way to generate recurring monthly income. Because the options are deep in the money (meaning the strike price of the option is at least 5% or 10% below the current stock price) they have a lot of intrinsic value. This is your downside protection. If the stock drops by the amount of intrinsic value between the time you sell it and option expiration then you’ve still made a profit. You’ve made the amount of time premium that was in the option when you sold it.
Buying large cap dividend paying blue chip stocks and then selling deep in the money calls against it is a common practice among conservative, income-oriented investors. The only real risk is that the stock drops below your net debit (stock price minus amount you received for the call option you sold), and if you stick to large cap blue chip stocks and write short-term calls then that is unlikely.