When bonfire night arrived, we introduced Mackintosh to his new harem.  What an absolute gentleman he was!  I mixed up some raddle paste and plastered his chest with blue goop, and in he went.  He instinctively knew what to do, and within 2 days Mrs B had been served.  Over the next few weeks (and several applications of paste later), all of the girls had blue bottoms so we know (theoretically) the order of who will have their lambs and roughly when.