you know what screw the pharma companies, such crooks!!
its all about blood flow. there are natural supplements that help with that which are totally legal that you can take only a daily basis or just a couple hours before.
http://w3.teststackrx.com/109.html << that's the link to the one I take. I take 3 caps per day and I am a walking boner.
the funny thing is the same ingredient in the supplement is what is used in Viagra! if you aren't willing to grow it in your backyard then just buy the supp instead