At team sessions his redshirt freshman year at Kansas State, Cosh would look to Collin Klein, a redshirt sophomore at the time who initially hosted Cosh on his official visit.
"Every little thing, he'd write it down. Coach said it, he'd write it down, everything," Cosh said. "I got to see that and I always thought, 'Why is he doing that?' As a young kid, 18, I didn't know anything."
Cosh had picked Kansas State, he said, partly because his dad was Bill Snyder's defensive coordinator at the time. He says he "felt comfortable in a sense."
He'd see Klein, the future Heisman Trophy candidate, race with receivers in sprints. He'd see how upperclassmen powered through the weight room. This was what big-time football looked like, and this was what Cosh had always aspired to since being a boy who plastered his bedroom with posters of his dream schools that ran high-octane offenses.
"I'll be honest, I got humbled at K-State," he said. "You went from being that top dog and then you go to K-State, a big-time program. Everybody's good."
In January 2011, he came home one night to meet James Madison coach Mickey Mathews visiting at his house.
"He was just telling me it would be a good deal," Cosh said. "You know, what any recruiter would tell you. That's how the game goes."
The visit, Cosh said, was enough to fill him with a bright sense of opportunity at JMU.
"I made a rash decision," Cosh says now. "And I regret that. It's my fault."
Out of fall camp, Mathews went with a dual-threat player named Justin Thorpe, who was later suspended after a positive drug test. By then, Cosh was at the bottom of the Dukes' depth chart.
"We had high expectations for Billy," Mathews said. "He just never came to [fruition]. It just for whatever reason never clicked here. And that's about it. Nothing more, nothing less."
From the sidelines, Cosh watched another season pass him by, and a void was again overcoming him. That rush that came only on game days felt somewhere in the distance, somewhere back at Arundel.
Maybe he wasn't good enough, he thought. Maybe he wasn't tough enough. Maybe his dreams were foolish.
"I'm not gonna lie," he said. "Sometimes I thought about quitting."
He turned to his father often. Chris Cosh had taken 11 coaching jobs in 26 years at that point.
"He always told me to keep believing," Billy Cosh said.
His father knew this: "Once you make a choice," he said, "you've got to live with it."
Tate Omli had to repeat the name of his next roommate to himself. "Billy Cosh?"