Related:

• Instructors do it with less-on.
• How many aerobics instructors -- does it take to change a light bulb?
  Five. Four to do it in perfect synchrony and one to stand there going "To the left, and to the left, and to the left, and to the left, and take it out, and put it down, and pick it up, and put it in, and to the right, and to the right, and to the right, and to the right....
• Think until it hurts. -- Roy Thomso
• I can handle pain until it hurts.
• Virginity can be cured. Pledge now. Give until it hurts.
• Patient: "Doctor, it hurts whenever I do this." Doctor: "Well, then don't DO that!
• DUD Do Until Dead
• Spectroscopists do it until it hertz.
• Practice is the best of all instructors. -- Publiliu