You can use this indicator to create a trailing stop taking into account on the nATRPeriod previous days.
It also always go up as a trailing stop should. It only goes down the price reaches the trailing stop.
In true TradingView spirit, the author of this script has published it open-source, so traders can understand and verify it. Cheers to the author! You may use it for free, but reuse of this code in a publication is governed by House Rules. You can favorite it to use it on a chart.