My memory is faltering on this. Looking for the name or reference on a move I'll try to describe. (Keep in mind I'm
about 5 lightyears from RK's writing.)
Deck is fanned and the spectator touches the back of the card.
Right hand splits the fan and lifts the partial deck, still fanned, to show the spectator the bottom/chosen card. As the right hand half is close to returning to the left hand, the bottom card of the right hand half is pulled to the right as
the indifferent card is jogged forward by the left thumb, as the right hand half is placed back on the left hand stock. When the deck is squared the chosen card is placed or culled onto the bottom of the deck.
To sum it up. A chosen card ends up on the bottom of the deck, with what the spectator thinks is his chosen card outjogged in the middle of the deck.