Crystal Harris isn't holding anything back when it comes to the intimate details of her former sex life with ex fiance Hugh Hefner.

While appearing on Sirius XM Radio's Howard Stern Show, Harris told Stern that sex with Hef lasted "like two seconds." TMI, Crystal!

When the shock jock asked if Crystal ever had an orgasm with Hef, she said "no." The 24-year-old Playboy model then added:

    "Then I was just over it. I was like, 'Ahhh.' I was over it. I just like, walked away. I'm not turned on by Hef, sorry."

Find out who Crystal is now reportedly romancing ... after the jump.