LARAVEL - Not able to call a function inside a controller method

Here is comment method of CommentController

 public function comment(Request $request)
        {

    $comments = DB::table('comments')
                            ->join('answers', 'answers.id' , '=', 'comments.answer_id')
                            ->join('users' , 'users.id' , '=', 'comments.user_id')
                            ->where('answers.id', '=' , '9')
                            ->where('parent_id', '0')
                            ->select('comments.comment as comment',
                                    'comments.id as comment_id',
                                    'comments.created_at as created_at',
                                    'comments.parent_id as parent_id',
                                    // 'answers.aanswer as answer',
                                    'answers.id as ans_id')

                            ->orderBy('created_at', 'desc')
                            ->get();


 foreach ($comments as $comment) {
            echo $comment->comment_id.$comment->comment.'<br>';
            return $this->testingComment();
           }


public function testingComment(){
                    echo "testing comments function";
                   }

    }

I have this foreach loop , I am just t trying to call this testingComment function in loop, but its not working.

I am building a nested comment system and i want to call function inside foreach loop to render child and sub child comments when a when a parent_id matches

via waq