Tahajjud is prayed in 2 rakah increments. The sunnah is 2, 4, or 8 rakah...but you can prayer 50 if you really want. So after 2 rakahs, you just stand up and do 2 more. You can take a break if you like between each 2 rakahs....its meant to be fairly continuous . The emphasis is on the amount of...