jQuery(document).on('lrm_user_logged_in', function(response, $form, action) {
if ( "register"=== action && response.data.user_id && $(".um-153").length > 0 ) {
// $(".um-153").length > 0 is optionally to check if your form is loaded on the page, like
// DO your ACTION like
my_send_teacher_msg(response.data.user_id);
}
});