Steve-O Says Zeke Elliott's Self-Tat's Douchey But Hilarious, I Would Know!

"I think that it's perceived as kind of a douchey thing to do, but that's why it's funny!"

That's Steve-O -- the man who made getting tattoos of himself on himself famous -- weighing in on Ezekiel Elliott's tat ... and, spoiler alert, the guy LOVES what the running back did!

"Everybody's favorite topic of conversation is themselves," the former "Jackass" star tells TMZ Sports ... "So, why not just celebrate that?"

Remember, Steve-O once inked a GIANT pic of himself on his back ... and in case ya forgot what it looked like, watch the clip -- he showed us how it's aged over the years.

So, when got him out in L.A. on Tuesday ... we had to ask for his thoughts on the Dallas Cowboys superstar getting his mug etched into the side of his calf earlier this month.

No surprise here ... Steve-O says he's ALL FOR IT!!!

"You gotta have the ability to not take yourself too seriously. Poke a little fun at yourself. 'I'm self-centered, I enjoy myself,' and I think that's funny, you know?"