Given that you need to be able to easily update your Adult Site with new videos, trailers, photo galleries and other content, what you need for a professional adult web design is a Content Management System or a CMS. WordPress is a well known and easy to use CMS, and you can indeed use WordPress to design a XXX Website.
There are also CMS that are especially tailored to the Adult Entertainment industry. Two of the best expendx.com and adultsitecms.com, with the former being the platform Playboy, Penthouse and other heavy hitters actually use.
Once you’ve figured how to handle updating your content and separating members only content from your teasers and trailers, you need to handle the other crucial aspect of adult web design which is Billing. This can be tricky because the most popular online payment platforms such as PayPal and Authorize.net don’t accept payments from adult themed sites.
Two options that you do have for integrating billing with an adult site are CCBill and ePoch. Each of these charge 14.5 %. Lastly, if you want to be able to give your members the option of being able to pay with their VISA card, you need to know that this entails paying a $750 usd startup fee.