I slipstreamed an hour behind a truck and my fuel consumption was more then halved

I was behind in a truck with "dirty" air, slapping my naked bike left to right. So decided to test out slipstreaming like have seen cars do and wow it's amazing. You have no wind pressure at all. Consumption went from 2.81 per 100km to 1.2L per 100km. I wouldn't recommend anyone to do it because if that truck brakes, chances of you colliding with that truck is high. Crazy to think more than half of the fuel goes to just defeating the wind.