Get Child Items from Term set c#

Our navigation is term driven... and I can use the following method to get the term items for each section.

It returns something like this

Parent

Parent

Parent

What I need is 

Parent

  child
  child
      child

Parent

 child
  child
      child

Parent

I have this method which gives me the parent but I cannot seem to get the child.

 public static void GetTermSetData()
        {
            ClientContext clientContext = new ClientContext("https://cloud.sharepoint.com/sites/mydeveloper/");
            SecureString passWord = new SecureString();
            foreach (char c in "XXXXXX".ToCharArray()) passWord.AppendChar(c);
            clientContext.Credentials = new SharePointOnlineCredentials("email address", passWord);
            // Get the TaxonomySession
            TaxonomySession taxonomySession = TaxonomySession.GetTaxonomySession(clientContext);

            // Get the term store by name
            TermStore termStore = taxonomySession.GetDefaultSiteCollectionTermStore();

            // Get the term group by Name
            TermGroup termGroup = termStore.Groups.GetByName("Site Collection - cloud.sharepoint.com-sites-mydeveloper");

            // Get the term set by Name
            TermSet termSet = termGroup.TermSets.GetByName("Primary Navigation");

            // Get all the terms
            TermCollection termColl = termSet.Terms;

            clientContext.Load(termColl);

            // Execute the query to the server
            clientContext.ExecuteQuery();

            // Loop through all the terms
            foreach (Term term in termColl)
            {
                // Display the term name
                Console.WriteLine(term.Name);

            }

            Console.ReadLine();
        }

Any help is appreciated.

sayitfast