Aaron Rodgers says he’s going on a ‘darkness retreat.’ What the heck is that?

It was a head-scratching comment for many people, who have never heard of the exercise before Rodgers mentioned it on the Pat McAfee Show. And, as you’d expect, there was more than a little bit of mocking on Twitter.

What is a darkness retreat, though?

At its core, it’s a spiritual exercise that ties back to Tibetan Buddhism. In practice, it means isolating yourself in a room devoid of light or other sensory distractions and staying there for an extended length of time, according to several places that offer the experience. Rodgers says practitioners are free to leave at any time, if they choose. Meals are delivered, generally twice a day, via a small double door food box, so no light gets into the room.

Fresh air is generally pumped into the retreat and there is a heated shower and bathroom along with drinking water.

“It’s a room, it’s a little house,” Rodgers explained. “There’s a two-way, like a little slot where they will drop in some food for you. But it is isolation and darkness, no music, no nothing. Just myself, isolation. I’m still in the art of contemplation about my future. After my isolation retreat, I’ll be ready to make a decision.”

Proponents say this sensory isolation can lead to moments of pure consciousness. The experience has been said to produce hallucinations on par with DMT, a psychedelic drug. If nothing else, it’s a change to catch up on sleep.

“It’s just kind of sitting in silence, which most of us never do,” said Rodgers. “We rarely even turn our phone off or put the blinds down to sleep in darkness. I’m really looking forward to it.”

Rodgers retreat, which will begin after Super Bowl LVII, is a short one. People with extensive meditation backgrounds often stay in the darkness for longer.