If you email the support of any porn site, ask them if they accept bitcoin.
You'd be surprised at how many will say "yes".
Accepting Bitcoin is so easy and basically free that you must be an idiot to not accept it. All merchants ever don't accepting Bitcoin are just ignorant about it. They are losing on a potential economy that they don't even know to exist. I think most of them who have heard about it are waiting for a "snowball effect" to ensue.
what you reply is correct after knowing about the bitcoin potential all the porn sites are ready to make it their another payment option because they open the site for income and if more users ask bitcoin then they will sure add it.