Best practice to create new Master-Detail objects (Laravel 5.1)

I've got 2 classes in my application both have their own Controller. Week -> WeekController Day -> DayController

When a new week is created I also want to create 5 (work)days for that week.

At this point I make a call from the create method in the WeekController to the create method in the DayController:

app('App\Http\Controllers\DayContoller')->create($week->id);

This post mentions this as being a bad practice. The alternatives offered however don't seem better in my case: A week doesn't really extend a day and using a trait would feel strange to me in this scenario as well.

So I wonder, what's the best solution in this scenario. I'm pretty sure this is something that's pretty common.

via Chebli Mohamed