After a night of dipping your dilly-wag multiple times, the love-juice excretions solidify on the Willy's eye... When nature calls (usually sooner if alcohol is involved), the male cautiously prepares to expel the undesired kidney extract (usually in a toilet). If lucky, a dual stream is presented. The goal is then to manage both streams for as long as possible without...
1) Collapsing the stream, thus 'Crossing the Streams', which is extremely bad!
2) Wielding any of the streams off-target. If the streams get too wide for the bowl, you fail!
The other night I held a dual stream for 25 seconds, both with equal power and no collapse!