Easy but difficult 4
Ready to continue stroking? haha.... how sensitive is your cock now?
So before you stroked 600 times and timed yourself, I think you can beat your own time hahahahaha - what do you think?
http://www.online-stopwatch.com/countdown-timer/
Open up this link to the countdown timer, put in your last time, press start and then stroke 600 times before the countdown timer rings.
If the timer expires before you complete your 600 strokes, you must start again!
And to be a bitch, on every attempt - YOU MUST STROKE 600 times. For example, if you stroke 550 times when the timer goes off - you must still stroke the final 50 strokes to complete the 600 strokes before you can reset the timer and start again.
Its in your interests to get this right the first time - otherwise all those strokes are going to get really sensitive.
And to make this even harder - you are not allowed any warmup strokes, start the timer and then start stroking.
When you have successfully completed the 600 strokes in a faster time than before, hit continue