Rocket Flower refresh
A Rocket Flower Refresh is a method of refreshing the timer of a Rocket Flower without returning to the pickup area, allowing Mario to travel indefinitely without it expiring. If Mario performs a Rocket Flower Refresh, the Rocket Flower will behave as if he picked it up again from its original spawn point, without actually needing to be in the spawn point's vicinity.
Methods
Standard method
The most common method to perform a Rocket Flower Refresh is using a ground pound. To perform this method, simply spinthrow and then immediately perform a ground pound while carrying a Rocket Flower.
It is important to note that the ground pound must be performed quickly enough after the spinthrow, or Mario will lose the Rocket Flower. Most players prefer to jump, spinthrow and then press ZL/ZR to accomplish this, although some will spinthrow before jumping.
Bonk method
The bonk method works similarly to the standard ground pound method, but is somewhat less convenient since it requires locating a wall to bonk on. This method simply requires running into a wall immediately after performing a spinthrow. Similarly to the other method, bonking too late after the spinthrow will result in a failed attempt.
2-frame method
The so-called "2-frame" method is by far the hardest method of performing a Rocket Flower Refresh, and involves collecting a moon immediately after performing a cap throw. It is named as such because the cap throw window is believed to be only two frames.
Under normal conditions, the cap throw must be either a spinthrow or an upthrow, but there is video evidence of a 2-frame refresh being performed with a standard cap throw. It is not currently known what the conditions are to perform this trick with a regular throw.