This embellishment is done with either foot before taking a forward step. Any time the leader leads you to step forward you can point your foot and tap behind yourself before moving through. Keep the knee of the leg doing the tap tucked behind the knee of the standing leg, bend the free leg, and let the tap happen from the knee down. These taps behind can be tiny and very close to the ground or you can bounce your foot almost up to your bum so the embellishment looks almost like a boleo.
This embellishment is usually done on the 'and' count between steps and the follower has to find her own way to fit it in. (She is not given extra time.) You could try it any time the leader walks backwards (one step, or many steps as in a back corrida), or as you go forward in an ocho cortado. Make sure you land right on the whole beat again in your forward step after tapping behind. Usually the emphasis of the tap is on the 'up', not the 'down' into the floor. Pretend the floor is a hot skillet and the tap burns your foot so you must pull up quickly.
Make the tap really tiny so it hardly bounces off the floor at all.
Make the tap big (if you are not on a crowded floor) so it bounces hight off the floor.
Put the emphasis of the tap down into the floor, almost like stubbing your toe behind you, so the movement becomes very heavy and staccato rather than light.
Try, if you are fast, to do 2 taps behind.
Exercises for Home
Practice walking forward, doing one tap behind yourself with each step. Try not to let the tap slow your forward movement or make the step become jerky. (You don't want the leader to feel your whole body move when you do this). Try all the tap variations above as you walk. Then see if you can do 2 little taps behind as you walk - this is hard!
Exercises for the Bus Stop or Grocery Line
Stand on one leg and tap the free leg behind you repeatedly, making sure the leg is moving only from the knee down. This is great for building your hamstrings! See how fast you can tap, or high you can tap. Try to do it without holding a wall