I thought this person was being sarcastic. As in, she gave it to him after a month whereas other girls don't give it to them (men) after however long. Like it was an indirect diss towards her (even though they don't know if they actually did do anything).
Maybe I'm translating wrong but that's what other comments are also implying.
PS. I'm not saying they did anything together. For all we know, they could have slept in different rooms. However, this is what a lot of the Knet comments are implying. They're literally calling her easy. And no, this isn't my opinion. I think the comments are quite mean.. Only sugarcoated to make them sound nicer.