Prom 64 (Berliner Philharmoniker/Rattle)<br/>Prom 62 (Gustav Mahler/Davis) <br/>Prom 61 (BBC Symphony Orchestra/Belohlavek)<br/>Prom 63 (BBC Singers/Hill) Royal Albert Hall, London

A highly charged performance of some of the most erotic music in the orchestral repertoire is as classy as it is explicit

It was, as my companion put it, classical music's answer to a Barry White album: a programme celebrating carnal desire in all its shuddering, sighing, yearning, yelping, convulsive ecstasy. From the first bold connect of Wagner's Prelude to Tristan und Isolde, through the luxuriant ache of the Liebestod, and on to the celestial dances, starlit arias and interplanetary whoops of Messiaen's Turangalila Symphony, the subject of Sir Simon Rattle's performance with the Berliner Philharmoniker at the Royal Albert Hall on Tuesday (Prom 64) was sex.

Rattle has often been criticised for favouring precision over colour, yet his Wagner was described in the vaguest of gestures. If the ensemble in the first 17 bars was tenuous, and became more so as the music tumbled forward to climax after climax, the sound quality was simply extraordinary. The Prelude can be read as a description of separation; a warning. But Rattle's heady, impressionistic soundworld was an explicit illustration of the two lovers' compulsion to merge into one, his Liebestod a farewell from an Isolde still caught in that moment. Brilliant with the intense sheen of the Berliner Philharmoniker's searing strings, lustrous brass, virtuosic percussion and glowing woodwind, Turangalila had a lyricism that belied the dazzling complexity of the score. Highly disciplined and lucidly argued, beautifully honed in the humid harmonies of "Jardin du sommeil d'amour", minutely balanced in each crazy-mirror configuration of orchestral soloists, this was a magnificent performance from Rattle, pianist Pierre-Laurent Aimard and ondes martenot player Tristan Murail.

Speaking of music and sex, I was tickled to see Alex James, erstwhile contestant in BBC2's Maestro, waving the flag for classical music in The Sun, last week. Tchaikovsky was his hot tip for lovers, offering "a different class of shag", while Beethoven was recommended as "cooking music". Crumbs. At 20 minutes duration, Romeo and Juliet is certainly a more tactful choice for the bedroom than Turangalila, a work whose length would make anyone insecure. As to Beethoven in the kitchen, those listening to Monday's broadcast of Sir Colin Davis and Nikolaj Znaider's performance of the Violin Concerto (Prom 62) must have had to wait a long time for supper.

Leaning in to the first desks of the Gustav Mahler Jugendorchester, Znaider quietly uncurled his opening phrase as though admiring the properties of the D major scale for the first time. With such exquisite refinement of tone lavished on each note, the structure of the Allegro ma non troppo was inevitably compromised. Yet Davis and Znaider sustained their argument eloquently through the Larghetto, pausing here and there to allow oboe, bassoon and horns to comment, and on into a Rondo bubbling with contained energy. Only in Sibelius's Symphony No 2 was the full dynamism of this orchestra of potential principals released, its rapt, resinous sonority underlining how densely populated by Dvorak's wood-nymphs and water-nymphs are Sibelius's forests.

For all Davis and Rattle's daring, Jiri Belohlavek's performance of Verdi's Requiem (Prom 61) with the BBC Symphony Orchestra and Chorus and the Crouch End Festival Chorus demonstrated the value of pragmatism. This was Verdi as you would expect it: crisply delineated, carefully paced, with a "Dies irae" as terrible and isolated as Violetta's anguish in Act III of La traviata. Anchored by John Chimes's subtle timpani, Daniel Pailthorpe's plangent flute and the chorus's responsive and expressive singing, it was a powerful performance, marred only by mezzo-soprano Michelle De Young's vampish delivery of "Judex ergo cum sedebit", which, last time I checked, is neither a curse nor a come-on.

Car crash of the week was the BBC Singers' late-night performance of Messiaen's half-French, half-Sanskrit, pillow-talk babble of mutual enchantment, Cinq réchants (Prom 63), which together with Harawi and Turangalila form his Tristan triptych. Of the 12 singers involved in Messiaen's songs of spiritual and carnal delight, only Siâ*Menna conveyed the joyful delicacy of the melodies. The more overtly sensual the music, the more awkward conductor David Hill's gestures became, and the more self-conscious the choir.

For amuses gueules, the ensemble performed Le Jeune's sportif part-song "Revecy venir du printans" and, with improvised accompaniment from sitar player Nishat Khan, settings of the Song of Songs by De Sermisy and Brumel. Now I've never cared for added noodles in Renaissance polyphony, be they jazz or raga, but to describe this experiment as being as embarrassing as watching a curate shake his booty to Cornershop would be inaccurate. It was worse. There are some excellent musicians in the BBC Singers, but putting singers with heavy vibrato next to singers with none will never produce a lean, vibrant, blended sound of sufficient versatility and suavity to suit 20th-century and 16th-century music equally well.

Proms (020-7589 8212), until Sat