Considering half the people reading this are probably stoned, I wanna let you know to not freak out.  Testing isn't completed but early reports say the more weed you smoke, the more likely you are to face sexual dysfunction. 

If you smoke weed, you probably know it can makes you tired, lazy, and generally unresponsive.  Well looks like your dong is getting stoned with you.  According to a report on fitperez.com, 70 to 80 percent of your penis contains THC receptors, which suggests it may hinder your performance.   According to the report though,

While the studies on this subject are not yet comprehensive or fully conclusive, it’s important for people who smoke to realize that there may be long-term consequences to their actions.

Am I telling you to put down the bong for good?  Nah, but you might wanna pull back a little.  In 20 years, you won't remember all those bong rips, but you'll know your wiener isn't working.