Because of the number of collaborations, the album touches on several other styles. "Waiting Room", a song written and sung with Prince for Return of Saturn, evokes his R&B style over a drum and bass beat. "Hella Good", an electro rock song co-written with hip hop production duo The Neptunes, is inspired by the funk songs of the late 1970s such as Queen's "Another One Bites the Dust" and the Commodores' "Brick House". William Orbit, best known for his work on Madonna's electronica-oriented Ray of Light, incorporates trance music in the production of "Making Out". "Detective", one of the five tracks produced by Hooper, takes slight influence from pop music. The album's title track closes the album by tying together the many musical themes. It is slow dub song, with acid house-style bleeps and moans.
Stefani's vocals range from innocent to seductive, sometimes transitioning from one to the other within a song. Her lyrics are based on her relationship with Rossdale, whom she married less than a year after the album's release. Stefani is openhearted and unreserved as on Return of Saturn, but her approach becomes more immediate and instinctive. The lyrics are more youthful than those on Return of Saturn and detail partying and feelings of lust. An overarching theme on the album is Stefani's impatience in the couple's long-distance relationship. She discusses wanting to see Rossdale on "Making Out" and "Waiting Room", and she reveals her distrust in Rossdale on "In My Head". On "Hey Baby" she gives an innocuous account of the debauchery between her bandmates and their groupies during parties, as she observes the party. The lyrics of "Underneath It All" question whether or not Rossdale is a good match for her, an issue resolved in the chorus, which was written based on a journal entry where Stefani wrote the line "You're lovely underneath it all" about Rossdale.