Shannon was shown on last night's highlights episode promising to take legal action against the Channel 5 show's producers if they showed her bottom to viewers.
The Shannon sisters were involved in a spat with Denise Welch over the incident, which involved Welch pulling Karissa's pyjama bottoms down during a party session.
Afterwards, Karissa warned Big Brother in the Diary Room: "You're going to show my ass on TV, that's for sure.
"I'm not cool with that so I'm going to sue you guys. My management's not going to be okay with this... I do not pull my pants down for anyone."
Her sister Kristina added: "Everybody knows she's a really reserved person."
Karissa also complained to Big Brother about fellow housemate Frankie Cocozza, accusing the X Factor singer of "sexual harassment".
Celebrity Big Brother continues tonight (January 24) at 9pm on Channel 5.
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