Kendra told Life & Style: "I thought she'd be classy about things [following their split]. But it's not classy how she's opening her mouth the way she is.
"She should've kept her mouth shut, been a bigger person and just walked away. She looks like trash."
Crystal, 25, ditched the 85-year-old lothario less than a week before their planned wedding in June and has since claimed their lovemaking lasted "like two seconds".
She added: "Then it was just over it. I was like, 'Ahhhh.' I was over it I just like, walked away. I'm not turned on by Hef, sorry. He doesn't really take off his clothes. I've never seen Hef naked."
However, Kendra thinks Hugh should put the damaging revelations behind him and move on with his life.
She added: "Hef's been Hef for how many years now? He needs to move on and keep living his life!"