When she was 17 years old, "Jersey Shore" star Sammi "Sweetheart" Giancola chose the wrong night to sneakily borrow her sister's favorite jeans.

"Her pants looked better on me than my own pants," Sammi insists on the latest episode of "When I Was 17," also featuring "Shore" castmates [article id="1653844"]Vinny[/article] and Ronnie.

While getting dressed to go out for a party, Sammi snuck into her sister's room and snatched a pair of "super skintight" jeans. Unfortunately, she picked the wrong night to wear them.

"I'm at this party thinking I look hot," Sammi recalled. "And, you know, cops come knock on the door."

Fearing the cops and not letting the skintight jeans hold her back, Sammi and the rest of the partygoers booked it through the back door. Having escaped the house, Sammi challenged herself to hop a fence, only the pants weren't so willing to keep up with her. "I go to jump over the fence, and I hear [a ripping noise]. Literally, my sister's pants split."

Sammi made her way home, where she had to break the news to her sister that she had not only stolen the pants, but had managed to destroy them.

"She was screaming at me," Sammi said. "We were screaming at each other. Not a good time."

Now, years later, her sister doesn't seem any less peeved. "They were my absolute favorite pair of jeans," she said. "I would probably still be wearing them now."

Catch a "Jersey Shore" edition of "When I Was 17" -- featuring Vinny, Sammi and Ronnie -- Saturday at 11 a.m. on MTV.