GOLDEN, Colo. - The murky rules around super PACs are confusing at best, the only rule being that candidates and their campaigns are not allowed to "coordinate" with the groups raising unlimited funds for their efforts.

And that's about it.

Mitt Romney addresses his own super PAC's fundraisers in person, although he has said he's not allowed to talk to his former staffers that run the group. Newt Gingrich visited last week in Las Vegas with his biggest super PAC donor, Sheldon Adelson, who with his wife has given $10 million to the former Speaker of the House's effort. And Rick Santorum is traveling with the man largely bankrolling the pro-Santorum super PAC behind the effort to make the former Pennsylvania senator the 2012 GOP nominee: billionaire mutual fund manager, Foster Friess.

Santorum told ABC News that he "know(s) what the rules are" and "I don't think it crosses a line whatsoever."

It does shine a light, however, on the questions around the confusing rules of coordination and the obviously still friendly relationships between people willing to spend tremendous amounts of their own money to support a presidential campaign. And even those rules are hard to enforce.

Friess has been traveling with Santorum for several days. Last Monday in Bemidji, Minn., the 71-year-old bounded around the town with the candidate, wearing a sweater vest to the factory where Santorum's signature look is manufactured and during the tour of the town.

Tuesday he was again on the plane wearing his signature white cowboy hat, as he told jokes to staff and press.

"I don't think it crosses a line whatsoever," Santorum said, when asked if it could look inappropriate and how he prevents lines from being crossed.

"He's a friend who has been a friend for many, many years and has traveled with him in the past even before there was a super PAC and someone who I talk to and who gives me plenty of advice on how I say it and what I say and someone who has been involved in a lot of public policy issues that I've been involved in for years and again is someone I enjoy their company, but we never ever even begin to broach the topic of what the super PAC is or does or what he does or does with it," Santorum told reporters after an energy conference here. "That's to me is a completely walled off area."

It's clear advice is given. Monday evening, Friess was questioning staff about interviews the candidate was doing and he compliments Santorum on certain lines he thinks are more powerful than others. Friess first appeared on the trail the night of the Iowa caucuses in January, beaming at his friend's win and introducing himself to reporters covering Santorum's victory (that night it was of a virtual tie, he did not officially win until weeks later). Affable and pleasant to be around, he fits in on the laid back nature of traveling with the Santorum campaign.

Last week, when FEC forms were released, they revealed that Friess gave almost half of the funds to the super PAC supporting Santorum called the Red, White, and Blue Fund. Friess hasn't revealed how much money he's given the fund, but the FEC report said he donated $331,000, but this is all before Santorum's Iowa win.

In an interview with ABC News over email last week, the mutual fund manager says he will continue "to be supportive in helping raise funds for the Super PAC" and he's encouraged by Santorum's plan to stay in the race for the long haul.

"I think Rick's intention is to go all the way to the convention, about which I'm excited," Friess said.

In Montrose, Colo., Saturday, Friess was also on the trail and Santorum said he is "very fastidious about conversations I've had with him."

"We don't talk about any activity of the super PAC at all," Santorum told reporters. "I have no idea about what he's doing or how much he's giving and I don't want to know. We talk about family. We talk about other activities. He's very careful in that regard and so am I."

President Obama also has a super PAC working for him, although it only raised $1.3 million in the second half of 2011, according to the most recent Federal Election Commission filing.

The nature of the presidency makes it impossible for Obama to have a similar relationship with super PAC donors, but he has rubbed elbows with some, including Steven Spielberg, at campaign fundraisers.

Spielberg, a major benefactor to Priorities USA, gave $100,000 in July, according to the FEC.

Friess has said he will travel again with Santorum to this weekend's Conservative Political Action Conference in Washington, DC where Santorum will speak. In fact, Friess is slated to introduce Santorum at the conference.

Notably, Newt Gingrich will be introduced at CPAC by David Bossie, president of Citizens United, the group that helped usher in the super PAC era.