In other news, the age old dichotomy between self-sex and pair-sex has finally been, so to speak, penetrated:

"LOVERS know only too well that men usually need a "recovery period" after orgasm, and that sexual intercourse with orgasm is more satisfying than an orgasm from masturbation alone. Now scientists think the two phenomena might be linked.

Following orgasm, the hormone prolactin is released into the bloodstream in both men and women. The hormone makes us feel satiated by countering the effect of dopamine, which is released during sexual arousal.

Stuart Brody of the University of Paisley, UK, and Tillmann Krüger of the Swiss Federal Institute of Technology in Zurich, measured blood prolactin levels in male and female volunteers who watched erotic films before engaging in masturbation or sexual intercourse to orgasm in the laboratory.

Surprisingly, after orgasm from sexual intercourse, the increase in blood prolactin levels is 400 per cent higher in both sexes compared with after orgasm from masturbation (Biological Psychology, vol 71, p 312).

This explains why orgasm from intercourse is more satisfying than masturbation, says Brody. Since elevated levels of prolactin have been linked to erectile dysfunction, this may also explain why most men need a recovery period after sex."