‘Shark Tank’ entrepreneur cracks up the room with cheeky innerwear pitch — walks away with six-figure deal

“Do you find yourself putting on a pair of jeans that just don't fit right? Maybe they're too big or too loose or too flat,” the founder said.
PUBLISHED JUL 28, 2025
'Rounderbum' founder Jonathan Diersing pitching his business on 'Shark Tank' (Cover Image Source: YouTube | Shark Tank)
'Rounderbum' founder Jonathan Diersing pitching his business on 'Shark Tank' (Cover Image Source: YouTube | Shark Tank)

Business ideas on ‘Shark Tank’ get crazier with every season! But when a bizarre product lands an unexpected deal, it gets even crazier. Jonathan Diersing stepped onto the coveted stage in Season 9, seeking investment for his company, Rounderbum. The name speaks for itself, as it’s a men’s innerwear company. Though the product itself wasn’t bizarre, the brand name and presentation had the investors in stitches. During his pitch, Diersing explained how appearance plays a key role in confidence, and the Sharks seemed to agree.

“Do you find yourself putting on a pair of jeans that just don't fit right? Maybe they're too big or too loose or too flat,” the entrepreneur said. “Have you ever wished while getting ready in front of the mirror that you had a little bit more back here or even up here?” he said, pointing at his butt, then his chest. This had the ‘Sharks’ crack up! Diersing explained that women have had ways to change the shape of their bodies for centuries. But men, on the contrary, are “stuck with what they’ve got or don’t got.” When he finally revealed his product, the investors burst out laughing over its very obvious name.

He added that his products were designed to lift a man’s confidence to a whole new level. He revealed that his customers love the way the shoulder pads and Rounderbum underwear make them feel. “Not only do we offer your traditional compression shape, but we go one step further. We enhance the shape of your body from head to toe, giving you more lift and volume in the areas,” he added. “We're not just changing the way that people look; we are changing the way that people live,” Diersing declared. “So who's with me? who's ready to turn the square world into a rounder World?” he asked the ‘Sharks.’


 
 
 
 
 
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A post shared by Rounderbum MX (@rounderbummx)


 

For his presentation, he had a pair of twins on board to show a before-and-after example for his product. This bit again had the ‘Sharks’ laughing hysterically! But jokes aside, it was a product that solved a major problem with decent sales. Daymond John opted out of the deal because he admittedly didn’t understand the product. He also cited a conflict of interest with another company he had invested in. Mark Cuban also didn’t resonate with the product and simply decided to retrace his steps and let the other ‘Sharks’ fight. “I’ve got to believe in a product. I go commando, so I am out!” he said, making his fellow investors’ toes curl.


 
 
 
 
 
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A post shared by Kevin O'Leary (@kevinolearytv)


 

Kevin O’Leary was interested and offered $150,000 for 5% equity in the company along with a $2-per-unit royalty until he recouped $300,000. “That’s a dollar for each cheek,” he joked. Robert Herjavec also chimed in with a no-royalty deal, offering $150,000 for 20% straight equity. O’Leary immediately called him “greedy and savage” for the high equity ask. Since Herjavec wouldn’t budge, Diersing sealed the deal with O’Leary.

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