Full explanation — Straddle
A straddle is a voluntary blind bet, typically double the big blind, posted before the cards are dealt to increase the preflop stakes. The player who straddles usually earns the right to act last preflop as compensation for the extra risk. Straddling increases both the pot size and the variance of the game, and it is generally not a profitable move in isolation — players mostly use it to loosen up the game or as a table dynamic tool.