manipulate_post_counter.php

<?php //do not include this php tag

add_action ('genesis_after_entry', 'my_custom_loop_func');

function my_custom_loop_func() {
  if(is_home())
  {
    global $wp_query;
  
    if( 2 == $wp_query->current_post ) {
    echo '<div class="ad_between"> Hi I am Your Ad </div>';
    }
  }
}