Salvatore “Sammy the Bull” Gravano describes in a new interview how mob boss John Gotti told him he needed to be the Mafia’s “sacrificial lamb” — just to save himself.

“He said, ‘Sammy, the [wiretap] tapes are horrible. They make you sound like a monster. What are we gonna do? So I’m controlling all the lawyers. You’re gonna take the weight, the lawyers are gonna bring it out in court that you’re a monster. You killed all these people, took over the unions, took over businesses.’ Which I never did,” the notorious New York City underboss-turned-canary claimed in a YouTube interview last week — his first videotaped chat in more than 20 years.

Gravano — who, in his deal with the feds, eventually admitted to killing 19 people — turned on the Gambino crime family boss in 1992, helping to put away Gotti for life. Gotti — a.k.a. “the Dapper Don” for his manicured appearance and “the Teflon Don” because before that, federal charges never stuck to him — died behind bars of cancer in 2002.

“During the trial, you hear John complaining on the tapes. ‘Poor John Gotti, he lost control of this monster, Sammy the Bull. It’s him, not John. So I will go free, and you’ll do the time,’ ” he said, referring to Gotti’s approach.

“I said, ‘Are you sure that’s what you want me to do?’ ” Gravano claimed.

“In other words, I’m worried about the feds trying to put me away. I’ve been pinched all my life. I never faced my friend, my co-defendant, trying to put me away. ‘Is that what you really want to do? The streets needs me, the boss.’

He said Gotti told him, ” ‘You’re the sacrificial lamb.’ I said, ‘OK, sure, that’s the way it is.’ And I got in touch with the FBI, I flipped, and I was gone.”

Gravano received a slap on the wrist in exchange for testifying against Gotti, then ended up in prison for nearly 19 years on drug raps before being released in 2017.