Bartolo Colon on his memorable home run: Put it in the book!

Bartolo Colon’s home run, a where-were-you-when moment four years ago Thursday, had many of the hallmarks of a Little League long ball: Shock that it happened, unbridled joy from teammates and a minor mission to get that ball back as a souvenir.

After Colon rounded the bases, another youth baseball sentiment emerged: All Colon wanted to do was tell his father.

Colon revealed that and other details from his homer experience and other portions of his 21-year major-league career in his new book, “Big Sexy: In His Own Words” with journalist Michael Stahl, published this month.

The dinger is the timely highlight. On May 7, 2016, as the Mets played the Padres at Petco Park in San Diego, Colon had lots of family and friends in attendance, including his wife Rosanna. But his father wasn’t there.

“I was eager for the game to finish so I could call my Dad and tell him. After I was done pitching, I called him from the dugout during the last innings of the game,” Colon wrote. “I swear, my Dad was somehow more excited than I was, which also made me very happy. He said he expected it; he knew that one day I would hit a home run.”

The elder Colon might have been the only one to expect it. In his three seasons (2014-16) with the Mets, Colon became a cult favorite for the fan base in part because of his at-bats, which were frequently bad and sometimes embarrassing. Sometimes his batting helmet would fall off when he swung. If he made contact, it was typically weak, and he wouldn’t bother dropping his bat as he jogged toward first base.

A reason for the early struggles, via the book: During spring training 2014, his first in the National League after spending all but three months of the previous 16 seasons in the AL, he didn’t take batting practice due to a sore Achilles tendon. But over the course of two more spring trainings and two-plus seasons of plate appearances, that changed.

“Going into 2016 I felt much more comfortable at the plate,” he wrote, “and I wanted to do some damage against opposing pitchers.”

On that fateful night, Colon stepped up in the top of the second, with the Mets leading, 2-0, and Kevin Plawecki on second base with two outs.

“By then I’d developed the practice of letting the pitcher throw the first pitch by me, so I could see his throwing motion and figure out how to time my swing,” Colon wrote. “[Padres righthander James Shields] started me off with a fastball off the plate for ball one. He threw another that was on the inside part of the plate, but for a strike. I thought, ‘If he throws another fastball, I’m going to at least swing at it.' ”

Shields did, tossing a 1-and-1, 90-mph fastball over the middle of the plate. Colon swung hard and hit it hard.

“It was like living in a dream in that moment,” Colon wrote. “I knew I’d hit a home run because the bat didn’t vibrate. The contact was that solid. The ball flew a few rows back into the leftfield seats, close to the foul pole, but it stayed fair.

“I enjoyed my trip around the bases. As I approached first, the Padres’ Wil Myers looked at me with his arms crossed, as if to say, ‘I can’t believe you just hit a home run.’ After I rounded second, I said to the shortstop, Alexei Ramirez, a teammate of mine with the White Sox who I played a lot of dominoes with, ‘I can’t believe I just hit a home run.’ ”

Two years later, Colon was in spring training with the Rangers and crossed paths with Shields, who was with the White Sox. Both were about to start what became the final year of their careers.

“He said something to me like, ‘Hey, do you remember that time you hit a home run off me?’ ” Colon wrote. “I replied, ‘No, I don’t remember any of it.’

“I didn’t want to make him feel bad. He laughed.”