if(player.getInventory().getItemInMainHand().isSimilar(customItems.entityDecapitator()))
{
    // player.getInventory().getHeldItemSlot();
    player.setItemInHand(customItems.activeDecapitator());
    // WAIT HERE
    player.getInventory().remove(customItems.activeDecapitator());
    player.getInventory().addItem(customItems.entityDecapitator());
}