Did you read the article?

> Basically, in the megamerge workflow you are rarely working directly off the tips of your branches. Instead, you create an octopus merge commit (hereafter referred to as “the megamerge”) as the child of every working branch you care about. This means bugfixes, feature branches, branches you’re waiting on PRs for, other peoples’ branches you need your code to work with, local environment setup branches, even private commits that may not be or belong in any branch. Everything you care about goes in the megamerge. It’s important to remember that you don’t push the megamerge, only the branches it composes.

> You are always working on the combined sum of all of your work. This means that if your working copy compiles and runs without issue, you know that your work will all interact without issue.

You don't even push the megamerge to the origin. Or perhaps you don't even need to push it. You can just... work off it.