Vacilón is a popular Caribbean slang term that means "partying" or "a good time". It's a fantastic word for a learner because its formal meaning is quite different.
Vacilón comes from the verb vacilar, which literally means "to hesitate" or "to waver". However, in the world of reggaetón, it has evolved to describe a lifestyle of fun, partying, and not taking things too seriously. When Plan B sings "sigue con el vacilón" (she continues with the party), they're painting a picture of a girl who lives for the weekend.
This track introduces us to Candy, a wild partygoer who lives life entirely on her own terms. Her family wants her to settle down and finish school, but she ignores all of it: "Sus pai la quieren ver casada que ella termine la escuela / Pero ella cambia más de novio que de panty" ("Her parents want to see her married and finishing school / But she changes boyfriends more often than underwear"). In Puerto Rican street Spanish, pai is short for padres (parents), and janguear is borrowed directly from the English phrase to hang out. While her sweet baby face convinces her grandmother that she is an innocent little angel ("La abuela de ella jura que es una angelita"), the reality is that her party weekend starts on Thursday and she leaves behind any boy who wants a serious commitment.
The real hook of the song is the clash between her high-class look and her wild bedroom taste. Plan B loves dropping Spanglish slang into the rhythm to nail this contrast: she might look elegant, but "Le gusta a lo kinky nasty y aunque sea fancy / Se pone cranky si lo hago romantic" ("She likes it kinky and nasty, and even though she is fancy / She gets cranky if I try to be romantic"). The beat keeps up with her frantic pace as the singers joke about her dodging drama, grabbing cash from her grandma, and unapologetically ditching sweet dates for loud nightclubs.