ex.php

<?php
 
// Option 1: the follow method immediately references the relationship and saves it.
 
class User extends Eloquent {
 
   public function follows()
   {
      return $this->belongsToMany(self::class, 'follows', 'follower_id', 'followed_id');
   }
   
   public function follow($userIdToFollow)
   {
      return $this->follows()->attach($userIdToFollow);
   }
   
}

// Option 2: The follow method just stores an array of follow ids, which you can save later.

class User extends Eloquent {
   
   public  $follows = []; // public just for example
   
   public function follows()
   {
      return $this->belongsToMany(self::class, 'follows', 'follower_id', 'followed_id');
   }
   
   public function follow($userIdToFollow)
   {
      $this->follows[] = $userIdToFollow;
      
      return $this;
   }
   
}

// And then, maybe in your repository:

class EloquentUserRepository {
   
   public function save(User $user)
   {
      if ( ! empty($user->follows))
      {
         $user->follows()->attach($user->follows);
      }
      
      return $user->save();
   }
}