‘American Idol’ Mansion — Swingers Warn Contestants — NOWHERE IS SAFE!!!

The “American Idol” finalists better watch their step in their Hollywood mansion — because no matter where they go … someone has probably already had dirty sex there … this according to two swingers who used to live in the house.

our sources broke the story … Idol’s current mansion was last occupied by a bunch of sex-crazed swingers for Playboy TV”s racy reality show “Swing” … about a random group of live-in swingers and their X-rated sexcapades.

Now former Swing-mates Michael and Holli tell us — NOTHING in the finalists” current digs was off limits for boning … especially not the Idol finalists’ music room, where the singers practice.

According to Michael and Holli, the room was a sex mecca — lined wall-to-wall with mattresses. Castmates even called it the Boom Boom Room.

But that”s not all — according to the swinger duo, the mansion”s former swinger occupants did it in the shower, on the floor, on ALL the countertops, outside, and their personal favorite … in the elevator.

The one exception: Michael and Holli insist the jacuzzi was a self-imposed no-bone zone … for hygiene”s sake. We still recommend wearing shower shoes.