A Tailpress shove-it is a Tailpress followed by a shove-it.  So you need to be able to Tailpress and Shove-it!  Once you learned these tricks, you can do this cool variation.  Ride up to the rail or box at a decent speed.  Put your front foot in the middle of the board, if its too far on the edge it will drag during the tailpress.  When u get on the object lean back and press with your back foot.  Keep your balance so the nose never touches.  When u reach the end push hard on the tail to get pop.  Use your back foot to spin the board 180 degrees.  Catch the board and ride away.