Companies and celebrities are being given the chance to protect their names from porn hijacking ahead of the launch of the .xxx web domain.
Brands can now request to have their name blocked from use with the new suffix, which goes live next year.
Existing adult entertainment sites can also submit their application to reserve a spot on .xxx
The "red light" suffix is intended to make it easier to find or avoid sexually explicit material online.
ICM Registry, which is administering the launch, said it hoped to "promote a responsible approach to adult content".
Brand and IP holders wanting to register now have 50 days - a so-called "sunrise period" - to submit their application.
Companies and individuals that do not want their name associated with pornography will be able to pay a one-off fee of between $150 and $300 (£100 to £200), depending on which company they register their domain with.
For example, UK adult star Teresa May might wish to bid for a .xxx domain, whereas UK home secretary Theresa May might consider protecting her name.
Conflicts over exact matching names will go through an arbitration process.
"Win, win, win"
Companies are under no obligation to go .xxx, according to ICM Registry's chief executive Stuart Lawley.
But those that did would contribute to an overall "win, win, win" situation, with benefits for adult content providers, web users in search of pornography, and those wishing to avoid it.
"Regardless of what your personal views are on the existence of pornography on the internet, at least .xxx will give people the information they need to make a choice," said Mr Lawley.
However, Jerry Barnet, chairman of the Adult Industry Trade Association, warned that anti-pornography activists would likely increase their efforts to block online adult content.
"I have mixed feeling about it," he told BBC News. "From the industry and freedom of speech point of view, I'm concerned that pro-censorship and morality campaigners will use this as an excuse to try and introduce some form of censorship.
"But from a business point of view it's kind of good for us because there are new names available, and that makes branding and site naming more interesting," he added.
ICM Registry does not process the applications directly. Firms must first approach a standard domain registrar in their home country, such as Go Daddy or Enom.
To ensure the registered porn sites do not harbour malware or present any other cyber security-related threats, ICM said they will be scanned daily by security firm McAfee - something that would make them safer to visit than many non-xxx sites.
The websites will be overseen by the International Foundation for Online Responsibility, and will be fitted with an electronic label to allow parents to adjust their browser settings and make sure children do not have access to certain sites.
After the sunrise period is over, a "land rush" period will run for 17 days, allowing prospective adult sites to register for the remaining .xxx addresses.
Following that, anyone else will be able to submit an application for non-reserved names on a first come, first served basis.