The Sydenham resident, 24, has created an advisory service to help men pick classy designer lingerie for their partners.

She launched the website a year ago after realising blokes often make costly mistakes when it comes to buying fashionable undergarments.

"I worked at a lingerie store while completing my double degree in business and psychology and we always had women come in to return items because they didn't fit or didn't match their tastes," she says.

"I realised there was a gap for luxury lingerie in the Australian market so went about designing a business model."

Ms Costabir, a former student at Lowther Hall Grammar School in Essendon, initially decided to open a shop in Melbourne but realised she could reach a wider audience by setting up an online store.

"The site offers a wide range of products and has tips for men who want to buy gifts for their partners."

Although the site has been a success with men and women alike, Ms Costabir hopes to expand her business by learning more about consumer behaviour.

"I'm looking at doing postgraduate study in psychology and hope to focus on consumer behaviour as it's important to understand how shoppers think."

She's urging men who are looking to buy lingerie for their partners on Valentine's Day to ensure they don't get the wrong size.

"They should check their partner's clothing to see what style and colour they like.

''If she wears full briefs there's a reason for it so he shouldn't get a completely different cut. It's important men don't deviate too much from what she normally wears."

More tips: The Lingerie Boutique