One marathon = 26.21875 miles
... x 5280 = 138435 feet
... x 12 = 1661220 inches.
Assuming you're packing 10 inches (generous?) and have a stroke efficiency of 80% that would be
1661220 / 10 = 166122 full strokes
... / 0.8 = 207653 80% strokes.
To plow an entire marathon would require over 200,000 strokes!
In Boston, Heartbreak Hill - or Dick Break Hill - kicks in around 20.5 miles = 163,000 strokes.
Use plenty of lube or there won't be any flesh left on your dick or her vagina.
"205,853 strokes! And you still haven't finished???"
What is the current time record for completing a fuck marathon (a full 208,000 strokes)?
Not to worry! You have two more months to practice and get in shape