hes saying he wants to (in the routine) place the black jacks facedown onto the table. He then wants the 7 and 9 to trap the eight once again (seemingly pointless). the spectator then looks at the "jacks" on the table, and sees that they are the 6 and the 10, hereby completing the production of a straight/climax to effect.
its good, but is it useful or just another kicker?