To add in new dragon races etc, simple in act_obj.c

    if(ch->race == race_lookup("dragon"))
    {
    if (CAN_WEAR (obj, ITEM_WEAR_TAILEND))
    {
        if (!remove_obj (ch, WEAR_TAILEND, fReplace))
            return;
        act ("$n wears $p on $s tail.", ch, obj, NULL, TO_ROOM);
        act ("You wear $p on your tail.", ch, obj, NULL, TO_CHAR);
        equip_char (ch, obj, WEAR_TAILEND);
        return;
    }
    }
    else
    {
	send_to_char("You don't have a tail!\n\r", ch);
	return;
    }
    
Just add something like...

    if(ch->race == race_lookup("dragon")
    || ch->race == race_lookup("red dragon"))
    {
    if (CAN_WEAR (obj, ITEM_WEAR_TAILEND))
    {
        if (!remove_obj (ch, WEAR_TAILEND, fReplace))
            return;
        act ("$n wears $p on $s tail.", ch, obj, NULL, TO_ROOM);
        act ("You wear $p on your tail.", ch, obj, NULL, TO_CHAR);
        equip_char (ch, obj, WEAR_TAILEND);
        return;
    }
    }
    else
    {
	send_to_char("You don't have a tail!\n\r", ch);
	return;
    }

And so on.

It isn't the neatest way to do it, but it is how I felt like doing it. :P