Jameis Winston -- Mocked Crab Leg Arrest for Charity ... Says 'Deadliest Catch' Star

He knew he'd be a punch line ... but convicted crab thief Jameis Winston consciously decided to subject himself to crustacean mockery during a recent celeb event to help out a charity ... TMZ Sports has learned.

We spoke with "Deadliest Catch" star Capt. Keith Colburn -- who was at the Mike Alstott Family Foundation celebrity outdoor weekend with Jameis ... and he told us how it all went down.

"I had a giant king crab we were auctioning off," Colburn says ... when Jameis suggested that he should make a public spectacle out of the situation because he knew it would be "good press" for the foundation.

"He thought it was a gag, man!"

Colburn says Jameis couldn't have been a better sport -- and says, "He's an amazing kid."

Hey, if he could take a roasting from Kevin Hart ... he's gotta have thick skin, right?