A short riff on the saxophone used to indicate the arrival or presence of a sexy woman. Second only to the "bow-chicka-wow-wow" guitar when people make jokes about "porno music". It's hard to do subtly. The muted trumpet can be used to similar effect. The history of this trope comes from that the roots of jazz and R&B were musicians playing in brothels and burlesque houses. The musicians were supposed to play music to, ahem, enhance the experience. Many jazz musician's nicknames were often euphemisms, like Jelly Roll Morton, which reflected their roots as brothel musicians.