Django how to display all child objects under it's parent?

In my views I am filtering all parent parent objects. support_object = Contact.objects.filter(user=user,parent__isnull=True) . In my html I am showing all parent objects but how to show if any parent have child objects. I want to show all child objects under it’s parent.

html

{%for i in support_object%}
      parent{{i.name}}
      parent{{i.message}} 
      #here I want to show all child message of parent
        
{%endfor%}   

Can You show your models in order to understand how is the relations (or reverse relation) between parent and child.

Rigo-Villalta I will update very soon. please allow me few minutes

Assuming that you have a model class “Message” with a user as author you should loop over this again, but it can give you the n+1 problems:

{%for i in support_object%}
      parent{{i.name}}
      parent{{i.message}} 
     {%for m in i.contact_parent%}
        {{ m.message }}
    {%endfor%}          
{%endfor%}  

but you have to substitute “message” in “{{ m.message }}” by the name of the field in the class “Messages”

getting this error 'RelatedManager' object is not iterable after using your code.

models.py :

class Contact(models.Model):
         user = models.ForeignKey(settings.AUTH_USER_MODEL,on_delete=models.CASCADE,null=True,blank=True,related_name='contact_user')
         parent =models.ForeignKey('self', on_delete=models.CASCADE,
                            null=True, blank=True, related_name='contact_parent')
         sno = models.AutoField(primary_key=True,)