Here’s What The Girls Marmot manga is About:
Junhee’s a pushover and has somehow managed to lend out all his money. He finally finds a great part-time gig, but it’s only for women! In serious need of the cash, he dresses up as a girl only to discover the job he’s just applied for is a clinical trial on a libido pill for women.
Not only is he locked in for a week with five other (ahem, horny) women, they’re all women from his high school! How long before everyone discovers he’s not a she?