"My ideal taco is actually the taco I'm not supposed to have, which is the taco we have on taco night at my house," he hilariously revealed. "It's the crunchy corn shell with the good meat, just ground beef in there. It's all about the layering. The meats got to be hot and the cheese goes on first so that it melts."
"And then you're going to get in there with a little bit of tomato and lettuce -- but not too much because it's not a salad, it's a taco -- and then you're gonna throw some avocado on top and some sour cream and then a bunch of Cholula," he explained. "Maybe squeeze some lime on top and go to town."
Switching gears, Damon weighed in on his upcoming Jason Bourne film, which hits theaters July 29. When a fan asked if his character could ever beat his pal Ben Affleck as Batman in a fight, his response was epic.
"I think the answer to that is clear," he said. "I'll let you fill in the blanks."
Damon also revealed that to this day, one of his favorite movies he's ever starred in is Good Will Hunting, a film that landed both him and Affleck an Oscar for Best Original Screenplay in 1998.
"Good Will Hunting obviously is the most influential movie in my life, and in Ben's life, and bringing it to the screen kind of dominated our 20s," he explained. "It took five years to get it from the time we started to the time it came out."
"I would love to write another script with Ben; I love Ben, I love his work, he's been my buddy for 35 years," he dished of their friendship. "The big issue is time for us. We have a company together so we work on a lot of projects together, but to try to carve out the time is really tough."
The two are now busy balancing their careers with fatherhood. Affleck is dad to three children -- Violet, 10, Seraphina, 7, and Samuel, 4 -- with ex Jennifer Garner, while Damon shares three kids -- Isabella, 10, Gia, 7, and Stella, 5 -- with wife Luciana Barroso. (Damon is also stepfather to Alexia, Barroso’s eldest child from a previous marriage.)
"The thing about Good Will Hunting is that we were unemployed and we weren't writing the script on a deadline either," Damon remembered. "Nobody was expecting it, so we were just these two idiots in our basement writing this thing, and now we have all of these pressures of the lives grown-ups have."
Affleck and Damon starred alongside Williams in the Gun Van Sant directed drama.
"Working with Robin almost defies description. He was one of the most generous, loving, wonderful people I've ever met," Damon revealed about the late actor, who tragically died in August 2014. "He had this capacity that I've never seen on a movie set."
"When everyone started to get tired and started to flag a little bit, he would launch into standup," Damon continued. "We knew it was original because he was making fun of crew members and pulling them into these bits. It was like 15 minutes of the best stand-up ever that was just privately for us. Everyone would laugh and laugh and laugh, and then everybody would get this boost of energy and go back to work."
"[We'll] never be able to thank [Robin] enough for what he gave us," he concluded. "In my heart, that's where he is, as this person that I'm deeply, deeply grateful [for that] came into my life and changed it for the better."
Here are four more highlights from the no-holds barred interview.
1. Damon was asked to describe what his Jason Bourne co-star Julia Stiles smells like.
His reply? Simple and sweet -- "happiness," he stated.
2. His first thoughts when hearing "Jason Bourne" are… interesting.
"Definitely pimp slapping a knife wielding assassin," Damon admitted. "That's kind of the first thing, you know — it has absolutely no relation to my actual life, but I get to do it when I play Jason Bourne."
He also said his character is the opposite of James Bond. "Where James Bond always has the right gadget," he explained, "Jason Bourne never does, so he's got to just improvise."
3. He breaks down all the details on why he'll never call a hot dog a sandwich.
"I've never considered a hot dog a sandwich because a hot dog is a hot dog," Damon dished. "I mean, technically it comes between two pieces of bread, or one fold it into two, so I guess you can classify it as a sandwich. Then what would you call it, a hot dog sandwich? That's like a hat on a hat so let's just keep it as a hot dog."
4. Growing up, everyone told him not to be an actor.
When people ask him for advice about going into acting, he tells them "absolutely not, it's a terrible idea, don't do it."
"[I say that] because that's what everybody said to me, and I think that if you're going to make it in this business that is so full of rejection and hardship, you need to believe in yourself despite what everybody you love and trust tells you," Damon said. "It's a very personal journey, so that was very helpful."