To
ejaculate into a partners face through the use of a high
power fan, rather than traditional means.
Speculation of the origins of the German Jetstream
date back to WWII, where it was thought that Hitler would use the German Jetstream on Eva Braun. The use of this technique allowed him to taunt allied attacks with threats of Advanced German Jetstreams. It was believed to have been a plausible origin, as he was able to conquer europe by jizzing into a fan.
You're
fucking a girl, and right before you cum you bring out a fan. You jizz into the path of the fan, thus hitting the females face through indirect means by
way of the breeze. Afterwards you ask the
female "how was that German Jetstream?"