Speaking to Listen Before You Buy It, Waterhouse said of his songwriting technique that "it's really just everything that's in my head. It's the way that little fragments and other ideas work, the kinds of experiences that I have all coming together." "Raina" reflects this with personal, emotive lyrics that strongly a channel a particular emotion, filtered through vintage R&B styles - typical of much of Waterhouse's music.
The track is a classic love song - it's one of the slower numbers Waterhouse has recorded, and features straightforward lyrics that describe his burgeoning attraction to somebody he's just met, presumably the titular Raina. The chorus sums up the general sentiment of the song, repeating "I've got it for you" until the song fades out.
It appears on his 2012 debut album, Time's All Gone. Unable to afford session musicians, Waterhouse instead slowly built up his own backing band to perform on the record. The band later toured with him under the name of The Tarots.