There is a staking ‘warm up’ period (currently up to ~2 days) when you first delegate coins. During this period, the coins aren’t earning rewards or being counted toward the stake, and you also can’t freely move them. This further helps to prevent fraud and attacks. Once warmed up (activated), the coins earn rewards until you wish to remove them and initiate a ‘cool down’ period, which is the same type of event as a ‘warm up’ period, but in reverse. Once the cooldown period is complete, the coins are no longer delegated or associated with the validator, and you can freely move them.