Maybe he should have sung “99 Bottles of Beer.”

A never publicly heard outtake recording of a very intoxicated John Lennon singing a debauched version of Lloyd Price’s “Just Because” in 1973 is hitting the auction block today in Los Angeles.

Estimated to bring in $30,000 to $40,000, the six-minute-long recording dates to the period when Lennon separated from Yoko Ono for a time to live with May Pang – a period he later referred to as his “Lost Weekend,” according to auction house Bonham’s.

The session was recorded in LA, where Lennon had gone to work on a record with producer Phil Spector.

The tape begins with a slurring Lennon, warbling: “I wanna take all them new singers, Carol and the other one with the nipples, I wanna take ’em and hold ’em tight, all them people that James Taylor had . . . I wanna suck your nipples, baby!”

He later murmurs, “Just a little cocaine will set me right.”

The backing band speeds up and slows down to try to keep up with Lennon, but a male voice is then heard calling the session to a close.

The Spector session later fizzled because of Lennon’s drunken behavior.

“Although Lennon is intoxicated, because it’s John Lennon singing, it still sounds decent,” reads the description in Bonham’s auction catalogue.

Lennon’s “Lost Weekend” lasted for a year and a half. He and Ono reconciled and got back together in early 1975. Nine months later, they had a son, Sean.

Lennon later re-recorded “Just Because” and released it on his 1975 album, “Rock ‘n’ Roll.”

Several other Lennon items are up for auction, including a “War is over!” banner and an animation cel from “Yellow Submarine.”

lukas.alpert@nypost.com