Once upon a time in a place where little sperms grow, there was
a super jock sperm who spent all his time working out.  He did things
like lifting weights and running, his most important duty. All the other
sperm were very curious about his past times. "Why do you keep working out
all the time," they asked.  "Well," he said, "Of all us sperms, only one 
of us is going to make it to the egg.  And that is going to be me." 
Well, the other sperms just floated around waiting for the day to cum
(pardon the expression). And it did,
and they were off!  All those sperms racing along and far out in front
of them was the super jock sperm, racing so fast and so hard (ha HA )
that they couldn't see him any more, but they still kept cumming.  Alas,
then, away in the distance, they heard a loud piercing scream.  They
still kept cumming though.  And then in the distance the super sperm came
racing back, screaming with all his might, "RUN FOR YOUR LIVES! IT'S A
BLOW JOB!"