One thing that works for me is to angle your body and the deck slightly towards different spectators in the group as you are talking then you make the pass as you are rotating your body and deck from one spectator to the other. Just the movement of the deck along a horizontal plane makes a pass much harder to see and you are moving your whole body along with it and managing eye contact.
If they are really burning a hole into your hand you can always sneeze into their eyes and do the pass as they wipe the spit off their face.
If they are really burning a hole into your hand you can always sneeze into their eyes and do the pass as they wipe the spit off their face.