PHOENIX—Persons close to Jake Parmentier and Mike Seifkes told reporters Saturday that despite being full-grown adults with jobs and families, the two longtime friends were still incapable of greeting each other like normal human beings.

According to sources, the two men, both 36, seem to completely lack the capacity to greet each other with conventional salutations such as "Hey," "What's up?" or "How's it going?" and instead rely exclusively on a wide array of eccentric utterances and gestures.

"Sure, we all did stuff like that in college," said former roommate Joe Laskin, adding that it was not uncommon at the time for a chance meeting in the dorm hallway to begin with striking a pose and saying "Yeah, boyeeee" in imitation of hip-hop artist Flavor Flav. "After a while, I just grew out of it. But Jake and Mike are still going strong. I think they're more into it than ever."

While some friends said they have grown accustomed to watching Parmentier and Seifkes slowly circle each other like ninjas upon entering the same room, others admitted they still found the behavior off-putting.

"I'm honestly getting a little tired of having them around," said friend Carl Ruben, who told reporters of a recent gathering in which the two friends appeared on the verge of shaking hands like regular people only to reenact the stare-down between Rocky Balboa and Ivan Drago from Rocky IV. "I almost wish they'd do their little routines by themselves ahead of time and get it out of their systems. Then maybe we could be actual grown-ups when we're all together."

Despite Parmentier and Seifkes' persistence in greeting each other in an unusual manner, sources said that the two appear to derive no pleasure from the exchanges and that their pop culture references, nicknames, and inside jokes often seem spoken out of obligation.

"I get the sense they'd rather not flex like bodybuilders or pretend to go nuts on a bass guitar the moment they spot each other," said friend Sarah Tobey, adding that she had never seen Parmentier and Seifkes share a casual hug without it quickly devolving into a fake fight or pretend make-out session. "I mean, it's weird watching them make this exaggerated bow to each other and say "Ah-so!" but then have absolutely nothing else to talk about afterwards."

"I think each of them is waiting for the other to stop," Tobey added. "I'm pretty sure they'd both be relieved if that happened."

According to human behavioral experts, such rituals are common among friends who become exceptionally comfortable around each other.

"At this point, they've established such a high degree of familiarity that, for them, a simple hello would be more awkward than ironically speaking a random line from A League Of Their Own ," Stanford University psychologist Carole Herzig said. "It can take years of behavior-modification therapy to make the transition from a full-on Milli Vanilli–style chest-bump to an ordinary handshake."

At press time, Parmentier and Seifkes had just run into each other at the gym and had immediately begun performing the slither-like dance move made popular by Guns N' Roses frontman Axl Rose.