Block Tigger is a minigame featured at Rabbit's House in the 100 Acre Wood in both Kingdom Hearts and its Final Mix version. It is playable after obtaining the second Torn Page (typically after Monstro) and returning it to the book in Merlin's house in Traverse Town. The player character receives a Mythril Shard as a reward after finishing it, successfully or not. Reaching a score of 150 or more is part of the requirement to receive the Cheer ability later on as well.
The objective is to block Tigger as many times as possible, while saving as many carrots (fifteen) as possible, all within a time limit of one minute. Tigger will randomly jump from one carrot to the next, and a carrot is considered gone if he lands on it twice. Tigger can be blocked by standing underneath him when he lands, which you can do manually by running. But, he is generally both too hard to predict, and too fast to block, especially when he jumps to the other side of the field.
Which is where the 'Rush' command comes in, which unlike "Pooh's Hunny Hunt", is vital to getting a high score. The Rush command is only available when standing close enough to a non-buried carrot and when used will automatically cause Sora to rush towards the carrot Tigger tried to land on last. This means that you need to time it to only 'Rush' when he has already jumped, doing so in time will lead to sora blocking Tigger properly. Note that 'Rush' is not infallible, and can sometimes fail. At the end the total amount of times you blocked him is multiplied by the number of carrots saved for your final score.