This concept is actually quite simple, and I'll give you an example.
If you want to perform a task that takes roughly 7 hours, you could spend 1 hour every day of the week doing it.
Or... you could spend 7 hours on one day doing it.
Which one will be more efficient?
The second option. Why? Because when you spread the task across the week you have to pick it up and drop it 7 times.
Each time you pick it up and drop it you have to set up and get comfortable, figure out where you left off, get the momentum going, re-find a state of flow...
I used this exact method when I wrote my book and developed an online business alongside my third year at university.
Monday to Thursday was for university work, then I would "put it in a box to one side".
Friday to Sunday was for my personal ventures (batched).
You might be looking to become a content creator... if so, you could batch a week's worth of content in one single day.
Now this isn't universal, for example, reading every night or meditation in the morning doesn't have to be done all at once to "get it out of the way" - it's a daily practice.
I'm referring to tasks that simply need to get done.
It also doesn't have to be one task, maybe a group of tasks that require you to be in a certain headspace.
Give it a try and let me know, this one has quite literally changed my life.