(SOURCE)
A Rock Straddle goes a little something like this:
A player on the button wishing to straddle must indicate as much to the dealer by tossing $4, or double the big blind depending on the game, in front of the dealer button before the start of a hand. Once the straddle has been acknowledged, the pre-flop action begins with the player under-the-gun, just as it would during a normal hand. When the action makes it way around the table to the button he is skipped and it is then the small blind's turn to act. Once both blinds have taken their turns, play then reverts to the button, who has the last action pre-flop. Moreover, should a player raise before the action even gets to the button, he would still be skipped and receive the ultimate last action after everyone else made their plays. The only situation in which the button would not be skipped is if there were a raise and a re-raise in front of him.