Amplifica means "amplify" or "make louder." It's an interesting word choice in a song about dancing and music, as it directly relates to the act of enhancing the sound.
In the context of the song, the DJ is being told to "amplifica o som do grave" (amplify the bass sound) to get the party-goers, especially the "novinha" (young woman), to dance and "se acabar" (lose herself completely). It's a key action word that drives the energy of the track.
Get ready to move with DENNIS, MC Nandinho, and Nego Bam's