Limit related records in polymorphic many-to-many realtionship with Laravel

I am using Laravel 5.1 and I need to limit the number of related records I am pulling using a polymorphic many-to-many relationship.

What I would like to do is get a list of categories by parent_id. For each category then I'd like to only pull four posts.

I have have this working with the code below, but it results in a bunch of extra queries. I'd like to just hit the database once if possible. I'd like to use the Laravel/Eloquent framework if at all possible, but am open to whatever works at this point.

@foreach ($categories as $category)
  @if ($category->posts->count() > 0)
    <h2>{{ $category->name }}</h2>
    <a href="/style/{{ $category->slug }}">See more</a>

    {-- This part is the wonky part --}

    @foreach ($category->posts()->take(4)->get() as $post)

      {{ $post->body }}

    @endforeach

  @endif
@endforeach

PostsController

public function index(Category $category)
{
  $categories = $category->with('posts')
      ->whereParentId(2)
      ->get();

  return view('posts.index')->with(compact('categories'));
}

Database

posts
    id - integer
    body - string

categories
    id - integer
    name - string
    parent_id - integer

categorizables
    category_id - integer
    categorizable_id - integer
    categorizable_type - string

Post Model

<?php namespace App;
use Illuminate\Database\Eloquent\Model;
class Post extends Model
{
    public function categories()
    {
        return $this->morphToMany('App\Category', 'categorizable');
    }

Category Model

<?php namespace App;
use Illuminate\Database\Eloquent\Model;
class Category extends Model
{
    public function category()
    {
        return $this->belongsTo('App\Category', 'parent_id');
    }
    public function subcategories()
    {
        return $this->hasMany('App\Category', 'parent_id')->orderBy('order', 'asc');
    }
    public function posts()
    {
        return $this->morphedByMany('App\Post', 'categorizable');
    }

I have seen a number of links to this on the web, but nothing that has actually worked for me.

I have tried this solution without any luck.

$categories = $category->with('posts')
->whereParentId(2)
->posts()
->take(4)
->get();

I have looked into this solution by Jarek at SoftOnTheSofa, but it is for a hasMany relationship and to be honest is a bit beyond my sql skill for me to adapt it for my needs.