Access underlying DbContext (or run stored procedure) from Entity Framework POCO method - entity-framework

Question

Is it possible to access the underlying DbContext (the DbContext that has populated this object/has this object in its cache/is tracking this object) from inside a model object, and if so, how?
The best answer I have found so far is this blog post which is five years old. Is it still the best solution available?
I’m using the latest version of Entity Framework if that matters.
Here's a sample to clarify my question:
I have a hierarchical tree. Let’s say it is categories that could have sub-categories. The model object would be something like this:
class Category
{
string CategoryId { get; set; }
string Name { get; set; }
virtual Category Parent { get; set; }
virtual ICollection<Category> Children { get; set; }
}
Now, if I want to access all descendants of a category (not just its immediate children) I can use a recursive query like this:
class Category
{
//...
IEnumerable<Category> Descendants
{
get
{
return Children.Union(Children.SelectMany(q => q.Descendants));
}
}
}
which works, but has bad performance (due to multiple database queries it needs to perform).
But suppose I have an optimized query that I can run to find descendent (maybe I store my primary key in a way that already contains path, or maybe I’m using SQL Server data type hierarchyid, etc.). How can I run such a query, which needs access to the whole table/database and not just the records available through model object’s navigational properties?
This can be either done by running a stored procedure/SQL command on the database, or a query like this:
class Category
{
//...
IEnumerable<Category> Descendants
{
get
{
// this won't work, because underlying DbContext is not available in this context!
return myDbContext.Categories.Where(q => q.CategoryId.StartsWith(this.CategoryId));
}
}
}
Is there a way at all to implement such a method?