Having twins is daunting. But Neil Patrick Harris says it's been nothing but a blessing for him and David Burtka.

"I love watching them learn to understand language. And watching them interact with each other is fantastic," the actor, 38, and father to 15-month-old fraternal twins Gideon and Harper, tells Parade.

Having each other also gives the twins a natural companion, and someone to explore the world with, Harris adds.

"We're lucky that we have two because they always have a playmate and they get to learn complicated concepts like sharing and cooperation," he says. "They get to learn those things a little earlier because they're with each other all the time. Watching their minds tick is fun."

Elsewhere in the interview, Harris reveals what he does on his days off – and it sounds like it's relaxing.

"Sleep! Nap!" he says. "And I'm sort of a tool-around-the-garage guy. I've got a workbench and I like to fix things. Well, I like to say I'm going to fix things and then put them on my workbench and then never get to them!"

One indulgence is Twitter, which Harris says has brought him closer to his fans.

"It allows a kind of intimacy with people who want to follow you," he says. "You can toss them a funny joke or picture or story that's unique to you and doesn't come through the publicists and the studios. It's just straight out of my brain, into my finger, onto my phone, and off to Twitter!"