The White Collar star is set to play Cooper, Blaine's (Darren Criss) intense actor brother, in the Fox show's next episode on April 10.
"To me, the fun of the role was getting to play somebody who had such strong convictions and opinions about all of the wrong things and in all of the wrong ways," he told TV Line. "At the heart of it, he really does want to help his brother avoid the slings and arrows of being a young artist.
"He clearly hasn't had an easy road of it as an actor. And over the course of that path, he sort of developed his own short cuts and tricks of the trade, which are all horribly misleading and misguided."
Bomer later admitted that he based his performance on a number of "bats**t crazy" motivational speakers from early in his career.
"Sometimes there's a lot of gold in their advice. And then sometimes you're just scratching your head," he said. "I've definitely had crazy acting teachers... just completely bats**t crazy. I'm not going to name any names."
Bomer also said that he had an "incredible time" and a "lot of fun" working with Criss on Glee, but it was fellow co-star Jane Lynch (Sue Sylvester) behind the most memorable moment of his guest stint.
"I think Jane sussed out right away that my character was just all over the map, just a complete hot mess," he recalled. "So she said, 'Matt, on this take, just kiss me on the lips'. I said, 'Great. You don't have to ask me twice'. It was nice. She had a lovely lip gloss on."
Glee airs in the UK Thursdays at 9pm on Sky1.
> Matt Bomer, Darren Criss to duet in 'Glee'