Allowing the water from a shower to hit your chest in a way that it runs down and off of your weiner. You then thrust your hips so the water is flung off the weiner and and onto anyone who happens to be in range of your weiner water.
My girlfriend walked into the bathroom while I was showering so I opened the shower curtain and soaked her with WeinerWater.
When two or more people are in a shower and the male begins to perform the "helicopter dick" while standing under the shower head, resulting in the flinging of water into their partner(s) mouth(s).
"Ugh, I didn't want to re-straighten my hair today but my boyfriend kept flinging his wiener water on me and its starting to curl."