Orgasm-o-meter

  It would be great to have a bracelet or something you strap in your partner with a white to red scale for how much pleasure he/she is feeling when making love. The red would indicate the final climax. More sophisticated bracelets could hint vocally it's getting "warmer" or "colder". And even play "we are the champions", or "alleluia" at the end (if it takes too long)...