From what I hear of this, it's about how love can make you want to do impossible things ("sunbathing on the moon"), how it can be addicting ("First kiss just like a drug/Under your influence"/"You take me over; you're the magic in my veins"), how it seems like you can hear your heart beating when you're together (hence the title of the song), and how good it feels when you're with the right man/woman (the whole song, basically).
From what I hear of this, it's about how love can make you want to do impossible things ("sunbathing on the moon"), how it can be addicting ("First kiss just like a drug/Under your influence"/"You take me over; you're the magic in my veins"), how it seems like you can hear your heart beating when you're together (hence the title of the song), and how good it feels when you're with the right man/woman (the whole song, basically).