A token burn occurs after a scheduled announcement from Bitfinex. This means that customers know exactly when the exchange is destroying a large portion of their LEO holdings and when to expect the price to increase.
Following the official announcement channels of Bitfinex can give you a heads up as to when the burns will occur. When they do occur, you can expect an upward movement in LEO price as the supply is reduced.
The “burn” itself is simply the deletion of LEO tokens from public circulation. A specific amount of Bitfinex holdings in LEO are permanently destroyed and a healthy balance between supply and demand is maintained.