Forget about sex.com. You will not get that much traffic from them (they use to send traffic but now they added a pop up were the surfer has to confirm they want to exit the site). Just pin your pic to a couple of adult pin sites that do send traffic and concentrate on those.
I'm not going to tell you wich ones send the most traffic but I'm gonna give you a good one you should pin too, http://www.pinsex.com.
There's a thread here
http://m.gfy.com/showthread.php?t=1113664 with a list of pin sites. Just pin to all of them, check your stats and weed out those that don't work for you.
It also depends on what you are pinning, most surfers on pin sites like gifs, self shots and artsy porn stuff just like the tumblr surfers.