Michael Phelps Reveals He Wants Baby No. 2 -- And the Moment He Found Out He Was Going to Be a Dad

Michael Phelps is a natural in the pool, and, it seems, at fatherhood.

The 28-time Olympic medalist and his wife, Nicole Johnson, welcomed son Boomer in May 2016 (he made his adorable Olympic debut in Rio) and they’ve had a “blast” watching their son get older.

“We’re at the stage where we’re constantly looking out for him, because he’s grabbing everything,” Phelps, 31, tells PEOPLE with a laugh. “Boomer has a pretty short attention span though, so he’ll go from interested to not in a second.”

Phelps says he also sings goodnight songs and reads books to Boomer before his 7:30 p.m. bed time.

“Depending on his mood, he gets a story, but if he’s grouchy he goes right down,” says Phelps of his son. “And if he wakes up in the middle of the night, we sing a couple of songs and we’ll make up words to lullabies that we know.”

Boomer’s favorite tune?

“If you put B.B. King on for some strange reason, it calms him so much!” says Phelps. “If he’s grouchy, we put on something like that and he’s immediately soothed.”

Although Boomer isn’t brushing his teeth yet (“He’s only got six teeth,” says Phelps), he loves putting toothbrushes in his mouth.

Related: Michael Phelps Challenges Wife to Friendly Wager at Charity Poker Event: I’m Competitive!’

“Anything he can get his hands on goes in his mouth,” says Phelps, who teamed up with Colgate to raise awareness about water waste and remind everyone to #EveryDropCounts when brushing their teeth. “When he grows up we’re going to teach him more about water conservation, because when you brush your teeth for two minutes and leave the water running, you waste 4 to 5 gallons of water. That number is astronomical.”

Phelps says he’s also been teaching his son to swim in the family’s backyard pool.

“We basically hop in two or three times a week,” he says. “Boomer loves it, he floats around in our hands trying to swim butterfly. He loves being in the water and he doesn’t mind going under.”

The Olympian adds that Boomer might turn out to be an even better swimmer than his dad.

“He’s the direct opposite of me as a kid, he doesn’t like being on his back and that’s how I learned to swim,” says Phelps. “He’s a step ahead of me.”

Mommy and I hanging in the pool today!! @mrs.nicolephelps

A post shared by boomer phelps (@boomerrphelps) on Mar 16, 2017 at 5:32pm PDT

So, will Boomer be getting a brother or sister anytime soon?

Phelps says his family is trying to figure out “when a good time is.”

“Nicole and I, before finding out [about Boomer] thought we’d travel around the world for a bit and have a honeymoon, but sometimes life isn’t exactly what you think it will be,” he says. “We are so fortunate to have a healthy and happy baby and hopefully more coming soon, but we don’t know when.

“We’re going through life everyday happy and blessed with what we have. But I hope to have more kids in the future.”

This article was originally published on PEOPLE.com