The 48-year-old reality TV star revealed the sneaky tactic in the couple's new podcast, "Separation Anxiety" ... saying she initially couldn't risk having people find out what was going on behind the scenes.

"I could never really put you under your name in my phone," Pippen said. "So I had you under Marc Jacob."

"I didn't want anyone to know when you called me."

Marcus seemed to completely understand the reasoning behind it -- after all, Scottie Pippen is Larsa's ex-husband, who has major beef with Marcus' pops, Michael Jordan ... and the two knew there was going to be a lot of "interest" if word got out that they were dating.

But, the couple decided to say to hell with the hate after a few months ... which was made clear after they started packing on the PDA wherever they went.

Marcus also spoke about how things got started ... and apparently Yo Gotti was right, 'cause it really does go down in the DMs.

"I do remember going on a trip to the Bahamas, taking a big group of friends, hit you in the DMs just saying, 'Hey, look we going to the Bahamas, you're more than welcome to come,'" Jordan said.

"I'll probably say that's the first move."

Pippen also had a few words for the trolls who still don't believe she just met Marcus a few years ago ... since Scottie and MJ played together for over a decade

"Like, I threw your 5th birthday or something," Pippen said. "Like, no, by the way, I never met you before."

Larsa admitted she feared she would never find true love again ... claiming there was no one out there who really got her attention the way Marcus does.

"I think I might be single forever because there's no one that's cute, funny, smart," Pippen said.

"Then when you and I first got together, I was like, 'Oh, my God, this is the guy.' This is the guy I prayed for, 'cause I really prayed for a best friend and I feel like I got my best friend."