There is more to the Mitzva of Lulav than taking hold of the four species and making a Bracha. The preferred manner of performing the Mitzva is to wave the Lulav in all six directions. This includes the four horizontal directions as well as upwards and downwards. This waving is called נענועים.
The meaning of these Na’anuim is mentioned in the Talmud in מסכת סוכה as follows: One waves to the four directions to Him who owns the four directions. One waves up and down to acknowledge Him who owns the Heaven and the Earth. That is to say that the four species is an allusion to G-d’s having created all of existence, and there is none besides Him.
One is supposed to do this waving with great Kavana and הכנעה, surrender, that everything in this world depends completely on Hashem. In short, the נענועים is meant to be a highly spiritual exercise. Chag Sameach