say you are going 40 mph in "D" slap the shifter to the left and nail it the tranny will go to the lowest gear needed ( say 2 gear)to take off fast as it can,, then say you let it shift to 3(at 6100 rpm) then you want to go into drive again,, just tap (or slap) the shifter to the right 3 or 4 times and ,,,you are in drive just cruising along,, hope this is what you wanted to know.
jim