Melt the chocolate and add cayenne pepper to taste, enough to make the melted chocolate noticeably spicy. Add the melted chocolate and milk to a frother pitcher in a 1:5 ratio and steam. Pour the hot mixture into a glass cup up to an 1½ inches from the top. Add the pisco and a dash of Aztec chocolate bitters. Garnish with a pinch of nutmeg, cayenne, and orange peel.