When Hugh Hefner calls, you answer the phone ... and for Playboy playmate Karissa Shannon, that holds true even if it's during sex.

Steven Hirsch, founder of Vivid Entertainment, has personally watched the two-hour "kinky" sex tape featuring Hef's former girlfriend and her boyfriend, Sam Jones III. Even Hirsch was shocked to see the blonde beauty take the Playboy founder's phonecall during such an intimate moment. Whips, chains, bondage ... we're told it's all in there.

Hirsch, who wants to talk to Karissa and Sam about their options for releasing the tape, tells X17online exclusively:

    "There is no doubt this is the hottest tape ever. In terms of the sex, it's really good and really hot. May make sense to cash in and let this thing get out there. Karissa is one of the most beautiful girls to ever have a celebrity sex tape."

As for who released the footage, Hirsch confirms that he did not receive it from Shannon or Jones. He believes the couple didn't initially make the tape to sell because "she's not totally made up."

Hirsch also tells X17online that he has yet to see any XXX footage featuring Heidi Montag and Spencer Pratt, but he hasn't dismissed the reality couple yet. He still believes there is footage out there of the two, however in the tape he currently has, it only features Karissa and Sam getting busy.

It's no secret that millions of dollars are at stake. Will Karissa and Sam bite? The clock is ticking ...