When Austin Mahone stopped by 'Chelsea Lately' last night (June 4), the 'MMM Yeah' singer touched on a variety of different topics, including food fighting with Taylor Swift, "vibing out" while writing songs in the bathroom, and working at a bowling alley. (Check it out in the video above.)

"She's cool! She's really tall, and we had a food fight on the tour, which was really cool," he revealed about touring with Taylor Swift.

"On the bus?" Handler asked.

"No, in her room," Mahone replied, which immediately elicited a chorus of "oohs" from the audience -- and from the no-holds-barred host, who began joking with the singer about his relationship with T. Swift.

"She's a sweetheart, but don't date her, 'cause she'll write a f----g song about you," Handler said, to which he replied: "That's not the worst thing that could happen! … I mean, her songs are hits."

And speaking of hit songs, Mahone reiterated the fact that he pens his tunes in the bathroom.

"I bought these lights at the Apple store and they change colors, and it's such a good vibe in the bathroom," he said. "It's kind of weird."

So, before he was writing songs in the bathroom, what exactly did the pop star do pre-fame?

"I actually had job setting up bowling pins at a bowling alley," he revealed about his (very old-fashioned sounding!) first job. "They would make kids go back in the thing and set up pins after they got knocked down."

"What era are you from?!" Handler exclaimed, giving him a rough time. But of course that wasn't the only thing she gave him a hard time about, advising him not to end up like Justin Bieber -- which, yeah, puts Mahone in a little bit of an awkward position. (Update: The Justin Bieber video has since been set to private on YouTube.)

"I don't want that to happen to you. You need to be a little more responsible, you understand?" she said in the video. "You can't act like an a--hole."

"Yeah, I got you," Mahone replied.

Check out Austin Mahone on 'Chelsea Lately' in the video above.