Sintonizar means "to tune in," like tuning a radio or a musical instrument. It's an interesting word because it's not as common in everyday conversation as other verbs, but it perfectly captures the song's theme of connection.
In the lyrics, Diego Torres sings, "Ven a sintonizar, te quiero en éxtasis total" (Come tune in, I want you in total ecstasy). He uses this word to invite someone to connect with him on a deeper, more harmonious level, suggesting a perfect alignment of feelings and experiences.