(defun outline-move-subtree-down (&optional arg)
  "Move the current subtree down past ARG headlines of the same level."
  (interactive "p")
  (outline-back-to-heading)
  (let* ((movfunc (if (> arg 0) 'outline-get-next-sibling
		    'outline-get-last-sibling))
	 ;; Find the end of the subtree to be moved as well as the point to
	 ;; move it to, adding a newline if necessary, to ensure these points
	 ;; are at bol on the line below the subtree.
         (end-point-func (lambda ()
			   (outline-end-of-subtree)
			   (if (and (eobp) (eolp) (not (bolp)))
			       (insert-char ?\n))
			   (unless (eobp)
			     (forward-char 1))
			   (point)))
         (beg (point))
         (folded (save-match-data
		   (outline-end-of-heading)
		   (outline-invisible-p)))
         (end (save-match-data
		(funcall end-point-func)))
         (ins-point (make-marker))
         (cnt (abs arg)))
    ;; Find insertion point, with error handling.
    (goto-char beg)
    (while (> cnt 0)
      (or (funcall movfunc)
	  (unless (or (bobp) (eobp))
	    (goto-char beg)
	    (user-error "Cannot move past superior level")))
      (setq cnt (1- cnt)))
    (if (> arg 0)
	;; Moving forward - still need to move over subtree.
	(funcall end-point-func))
    (move-marker ins-point (point))
    (insert (delete-and-extract-region beg end))
    (goto-char ins-point)
    (if folded (hide-subtree))
    (move-marker ins-point nil)))