This soft acoustic love song may be quite uncharacteristic of the band's previous and future material. Guitarist David Gilmour composed the chord sequence, played in a series of arpeggios, and Roger Waters wrote the melody and lyrics. This song also features slide guitar work by Gilmour, as well as a fretless bass, played by Waters. The song begins and ends in the key of E major, with a darker middle section (following the lyric, "and the candle dies") in the parallel minor, E minor. Both the E major and E minor chords feature the ninth, making this song one of many Pink Floyd songs to feature a prominent E minoraddedninth chord, "Em(add9)". Throughout most of the song, the bass line remains on E as a pedal point, creating a drone. A chord named "G#m/E" is more accurately called an E major seventh chord, "Emaj7", and a "Bm/E" is just as equally named an "E7sus2". In the instrumental interlude, however, the chords change completely to A minor and B minor chords, leaving the E bass drone for a time before returning to E major.
According to Nick Mason, the song's title originates from a possible hand in the game of mahjong, with which the band had become enamoured while touring.
The song's lyrics refer to an eiderdown, better known in the U.S. as a comforter. Two other known Pink Floyd songs make reference to an eiderdown, Syd Barrett's "Flaming" and Waters's "Julia Dream".