I do not consider this
concept intriguing as much as I consider it
misinformed.
While it may be
true that a longer
penis would usually place the tip of the penis deeper inside the
vagina during
climax, I concur with TheLordScribe's observation that
semen is not seeped, but rather
ejected (compare throwing a
dart at a
dartboard from 10
feet as compared to 5 feet; although, you're not really aiming at a
target here. Well, you are, but if you miss it,
you've got bigger problems than penis size.)
There are a number of other
factors that have
far greater influence on whether one of your sperm makes to to
Checkpoint Charlie, a few being the
acidity of the vagina, how long its been since you last ejaculated (multiple ejaculations in a short period produce less and less ejaculate with each
orgasm), and your
overall health (if you have a
fever, you produce fewer sperm.)