Mix Courvosier, Drambuie and Gran Marnier in a brandy snifter. Top with 151. Do not disturb glass at this point. The recipient then lights the "float" of 151, and quickly douses the flame by placing the palm of the hand over the mouth of the glass. It will cause a bit of suction; do not be alarmed. Remove the hand and drain the glass quickly. Immediately cover the glass after drinking. When sufficiently recovered from swallowing this vile concoction, inhale the fumes from the bowl of the snifter, passing smoothly out of this world. A real evening ender. Or starter.