When the 13 EMA crosses up over the 55 EMA it is a sign to buy (long) OR a sell (short) if the line is crossing downward under the 55 EMA.
1. Stop loss placed somewhere on the opposite side of the 55 EMA . If candles previous on that same side then behind the one of those candles as well to put distance between candle levels.
2. Set a specific stop loss according to your money management tolerances, 10, 25 or 50 pips as your needs dictate.
15, 30, or 60 pips.