Janguear is a fun, informal verb that comes from the English phrase "to hang out." It's commonly used in Caribbean Spanish, especially in Puerto Rico, where Farruko is from.
In "Mi Forma De Ser," Farruko sings, "Vaciló y no paro de janguear," meaning "I chill and don't stop partying/hanging out." It perfectly captures the carefree, party-loving attitude of the song and is a great example of modern, colloquial Spanish.
Farruko builds this whole track around one repeated line: "Que digan lo que quieran de mí" [Let them say whatever they want about me]. He isn't arguing back — he just keeps doing what he was already doing, and dares the gossip to change anything about it.
The verses stack up the specifics behind that attitude: drinking, showing off, spending money the way he wants, refusing anyone's approval. "Solo por mi forma de ser" [Just because of my way of being] and "Vivo a mi manera, nadie me controla" [I live my way, nobody controls me] are the closest the song gets to a thesis statement. By the end it drifts from bravado into something closer to a shrug at mortality: "Por qué nada de lo material cuando te mueras te vas a llevar" [Because you can't take anything material with you when you die]. The party talk and the reminder that none of it lasts sit next to each other without resolving into a moral — that's the song's whole attitude in one move.