When you’re playing music in the Music app in iOS 7, there’s a thin red playhead that you can drag to adjust the song’s playback position. Tap and drag it around for what Apple calls “Hi-Speed Scrubbing.” (Why it’s not “high,” I can’t say. Maybe the programmers were hi.)

Here’s the hint: You can adjust the speed at which you’re scrubbing through the song, if you need finer-grained control: Tap and hold on the red line, and then drag your finger upwards.

As you drag up the screen, you’ll note that there three other gradations of scrubbing speed: Half-Speed Scrubbing, Quarter-Speed Scrubbing, and finally Fine Scrubbing; that last mode lets you scrub through the song second by second.

Source: Mac OSX Hints