A feeling he called inexplicable. A feeling, he said, that bubbles in your chest when you know something is right.
Never mind that Shelley was just seeing Tennessee's campus for the first time last weekend, he knew he wanted to be a Vol.
And the Scout three-star cornerback acted on that feeling Monday night, announcing his decision to pledge to Tennessee and giving the Vols seven verbal commits in the 2015 class.
"It was just time," Shelley told InsideTennessee. "That school is just amazing. It's what I wanted so I went ahead and did it."
After reflecting on the trip, Shelley was given the green light from dad and phoned Tennessee's defensive quality control assistant Terry Fair to break the news.
"He was really excited, which was awesome to hear," Shelley told IT. "I just had to take the time and talk things out with my dad before I decided. We talked about the overall school and we both just decided I fit in there and it was the right place for me."
The Tucker (Ga.) High School standout rattles off a list of things that stuck out to him while touring the Vols' program. He was "awed" by the new facilities, Neyland Stadium, the VFL program and more.
But Shelley said his fondest memory from the visit was speaking with current Tennessee players.
The nation's No. 38 cornerback spent time talking with Vols wideout Marquez North and described their talk as "eye opening."
"You can just the players are confident," Shelley said. "I like that a lot. The future is bright here and talking to guys like (North), you can just tell that they believe in the coaches and have no doubts they'll be contending in the future. I thought that was really cool to see. Tennessee is coming up, I'm telling you."
Shelley said he also enjoyed spending quality time with Tennessee defensive backs coach Willie Martinez over his visit and described their relationship as "excellent."
"All the coaches, they're just different," Shelley said. "I trust them. That was a huge thing for me."
At 170-pounds, Shelley said his biggest goal over the offseason is to put on weight. But he doesn't see that being a problem, especially once he enrolls at Tennessee.
"I was talking to some of the early enrollees, too, and they said they've all put on like 19 pounds in a blink of an eye," Shelley said. "I thought that was really awesome. They develop guys here and treat them well. I'm excited to be part of the family."