"Down in the boondocks." joke

A guy and his manager go down to the docks. The manager is betting
every longshoreman he sees that his guy can screw and satisfy 100
women in a row, without pausing. Bets are made and they agree that
they'll meet the next day.
The next day, 100 women are lined up along the dock and the guy drops
his pants and starts. True to his word, he moves from one to the
next, satisfying each one without pausing: 1.. 2.. 3.. on and on he
goes: 49.. 50.. 51.. He slows down somewhat: 83... 84...
85... but he is still moving from one to the next and the women
are still satisfied: 97... 98...
99... and before he can get to the last woman he has a
heart attack and dies.
The manager scratches his head and says, "I don't understand it! It
went perfectly at practice this morning!"