Start out with a basic jack, then have participants add a tuck. Once they are used to this, add a leg extension (both legs extend forward) then go back to a tuck. this move is jack, tuck, extend, tuck) every part of this move except for the jack is performed with both feet off the floor.
This move should be demonstrated in the water so that you can show the full move. This is a great move for working the hipflexor, hamstring and abs. Abs should contract when tucking knees into chest.