Janguear is a fun, informal verb that means "to hang out" or "to party." It's a Spanglish term, derived from the English phrase "to hang out," and is very common in Caribbean Spanish, especially in reggaeton and urban music.
In "Ponte Pa' Mi," Justin Quiles uses it when he sings, "Que salimos a janguear y tú luces letal" (We're going out to hang out and you look lethal). It perfectly captures the casual, party-ready vibe of the song and is a great example of modern, everyday Spanish slang.
Justin Quiles is here to shoot his shot in "Ponte Pa' Mi"! This song is all about him trying to convince a woman to give him a chance. He's clearly smitten, noticing how good she looks in the summer sun, saying she's "más buena, maldita sea" [so good, damn]. He's heard she's a bit closed off, but he confidently declares, "Ya llegó el que la abre" [The one who opens her has arrived].
He's ready to be her new man, pointing out that "desde hace rato, tú no tienes gato" [for a while now, you haven't had a boyfriend]. He wants to give her some "mantenimiento" [maintenance], which he playfully explains means things like kissing her back, and getting down to business. He's not shy about his intentions and believes he's a big upgrade from her last guy, telling her, "Para él tú eras un five, para mí tú eres un ten" [For him you were a five, for me you're a ten]. He's basically saying, "Ponte para mí" [Get with me]!