Don MacCarthy/London Ent/Splash News Online
07/26/2011 at 07:00 PM EDT
Crystal Harris is moving on from Hugh Hefner, but not without taking a few parting shots at her former fiancé.
Harris, 24, said Tuesday on Sirius XM Radio's Howard Stern Show
that sex with the 85-year-old Playboy founder lasted "like two seconds."
"Then I was just over it," she says. "I was like, 'Ahhh.' I was over it. I just like, walked away. I'm not turned on by Hef, sorry."
She adds that they had sex just once.
"He doesn't really take off his clothes," Harris says. "I've never seen Hef naked."
Now that Harris has parted ways
from Hefner, she is spending a great deal of time with Dr. Phil's son Jordan McGraw.
a reported romance with the songwriter in June, Harris was spotted out with him recently at Knave, the upscale and dimly lit bar at Le Parker Meridien in NYC.
"They were joined by two women who stayed for about an hour," an onlooker tells PEOPLE. "Crystal was drinking mojitos and laughing, and Jordan was sipping a drink on the rocks. But once their friends left, they really settled in and seemed more and more comfortable."