Mother-Daughter Duo Holds Hands During Colonic on TLC's sMothered : 'Have to Have Her by My Side'

How close is too close? There's no such thing, if you ask the stars of TLC's sMothered.

The reality show follows the lives of six attached-at-the-hip, over-the-top pairs of mothers and daughters with shockingly close bonds. And in PEOPLE's exclusive sneak peek at Sunday's episode, one of the duos, Mary and Brittani, head to a spa for a joint colon hydrotherapy session.

"I've had a colon cleanse before, but this is going to be Brittani's first time," Mary says. "After the colon cleanse, I feel amazing. But in the beginning, it's a little uncomfortable. I can tell by the look on Brittani's face that she's really nervous, so I think I'm going to go first."

The second she lies down, she grips her daughter's hand — much to the surprise of Erin, the owner of the spa.

"Colon hydrotherapy, or colonics, is water going into the colon, which flushes out the waste. It's just a very holistic approach to detoxification," she explains, admitting, "Mary and Brittani are the first mother-daughter that I have seen holding hands while they were getting colonics."

TLC

But Mary — who is clearly in discomfort, grunting and groaning — says she couldn't imagine doing it without her daughter.

"I have to have her by my side," she says. "She gives me that extra push — just the, 'Come on, let's do it!'"

TLC

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Mary and Brittani are one of three new mother-daughter pairs in the season 2 cast. The cast also includes returning stars Sunhe and Angelica, Dawn and Cher, and Kathy and Cristina.

sMothered airs Sundays (10 p.m. ET) on TLC.