Cross polination
when two guys piss in the same urinal or toilet bowl and cross their urine streams.
Joe: Hey chris, you wanna go cross polinate?
Chris: Cross polination? HELL FUCKIN YES!!!
Chris: Cross polination? HELL FUCKIN YES!!!
Cross Polinating
Using the same finger to pick the second nostril of one's nose immediately after picking the first.
The dude next to me at the traffic light was doing some serious cross polinating this morning.