My site of choice is actually youporn.com and i know exactly what you're talking about.
What is happening is the website is detecting your browser and giving a different version of the site based on that query. If i try to go to these sites from my iPhone 4, 3G or 4s it ends in the same result. On the iPad 2 I have different results though because these sites have HTML5 versions that are only able to be seen while on an iPad2.
The way around this is to get a browser that allows you to fake your user agent. Meaning that it will say you're using an iPad when you're really on an iPhone. The best browser i've found for doing this is Atomic Browser. It's 99 cents currently in the App Store.
If you currently have a browser with the ability to do this and it's still not working, this is probably because you've viewed this site from that browser prior to changing your user agent settings. By doing that, a cookie was saved on your phone so that the site doesn't have to perform the check again. To get around this, change your user agent to look like you're on an iPad 2, then clear all your cookies, cache, temp files etc from your browsers settings. Now go back to that site and it should show up perfectly fine.
Enjoy your extra time spent in the bathroom!
Way to educate the little kiddies about porn sites I think his mom and dad and your wife will be very proud of you.