Bollinger Bands
A moving average plotted with bands set a number of standard deviations above and below it, so the bands widen when volatility rises and contract when it falls.
Price touching the upper band is not a sell signal. In a trend price can ride the band for a long stretch, and the band moves with it. The more informative state is the squeeze: unusually narrow bands indicate compressed volatility, which tends to precede an expansion — without saying in which direction.