The site
It appears that there are a few rules in activity for training of the submissive in order to go through the act correctly. Thus any submissive who is going to work with DP will indeed need to train to be able to accept it as deeply as what is shown on DP Fanatics. From our understanding of those on whom this is practiced, it is of the upmost importance to relax during the entrance period of the DP. The more relaxed the subject is, the better the likelihood that all will go well, and there will be no anguish involved. This is because relaxed muscles can simply take it better, whereas if the muscles are tight, then it is a very difficult entry into the body regardless of whether or not the entry is being made into the anus or the pussy. The point is that there is already a body occupying most of the space up there. A caveat that we learned when we spoke to aficionados of DP was that the three best know each other very well and not feel squeamish about performing this act. The reason is, as mentioned, that the two cocks cannot help but feel as if they are rubbing together once inside. If one studies the anatomy of a female one finds that there is but one very insignificant membrane between the anal cavity and the pussy when we consider the inside of the female.
On the other hand, there are some who voiced a liking for just such an experience saying that it excited them even more than just entering this or that orifice because the feeling of the other cock tended to give them thrills that they did not feel with just “regular” ass or pussy fucking. We found this idea of the utmost interest and vowed that the next time the opportunity presented itself, we would opt for DP and become DP Fanatics ourselves as soon as we could. Returning to the site itself we studied the pictures even further. We noted that the male on the bottom who usually fucked the anal cavity would have to contort his cock in a rather unnatural manner in order for it to fit willingly and easily into the cavity of choice. Meanwhile, the second cock would not have to work that hand to maintain intromission.