[parenthesis]

> If it's something practical like programing or music that means applying the techniques to make something.

When a child learns a new word, they may go around gratuitously using it for a while.

When you learn a new concept or technique, gratuitously apply it in every way you can think of. Having done that, you will be able to use it appropriately when the need arises.

For example, in music, if I learn or discover a new kind of chord substitution, I will gratuitously apply it to a bunch of chord progressions. Then I'm left (hopefully) able to apply it when that sound is what I want, or when it solves a voice leading problem.