function cwc_mail_shortcode( $atts , $content=null ) {
for ($i = 0; $i < strlen($content); $i++) $encodedmail .= "&#" . ord($content[$i]) . ';';
return '<a href="mailto:'.$encodedmail.'">'.$encodedmail.'</a>';
}
add_shortcode('mailto', 'cwc_mail_shortcode');

Bu kodu bir denerminiz function.php ye