It turned out he wasn't too phased. "He said as long as I was comfortable he didn't mind," she says.
Sexologist Nikki Goldstein says the period / booty-call conundrum is familiar to most girls who are dabbling in casual sex and not using the pill to skip their monthly.
She advocates being playful with breaking the news so that the guy knows that sexy times are definitely on the cards, even if you're not willing to go the whole way.
"If you act like you are disgusted by it, you can transfer that onto him," she says.
"You could say something like, 'We can't do that this time of the month but there's the rest of my body to play with'."
Dr Goldstein says that a lot of men will be fine with going ahead with sex anyway.
"It shouldn't stop you if you do want to be sexual with someone," she says.
"We have got to bust the myth that periods make us un-sexy."
In fact, sex therapist Somerset Maxwell says that it's many women's favourite time of the month for bedroom antics.
"The tragic irony is that women are often really, really up for it when they have their period," she says.
Ms Maxwell advocates being upfront from the first booty call suggestion, and not making other excuses for being out of action, lest he thinks you're game-playing or fobbing him off.
"If it was a date, I would say there's no need to say anything but if it's a booty call the implication is sex and you have to give him the opportunity to be OK or not OK with it," she says.
"He might come across the city in a cab and if you haven't told him, you might find yourself in a negative headspace thinking, 'What if I tell him and he's pissed off?' or 'If he's come all the way here, then I have to get him off'. It could increase your pressure level and put you in a position where you're performing under duress."
If you're up for it but he's hesitating, Dr Goldstein says you shouldn't immediately judge him as anti-feminist.
"A lot of people have a fear of blood so you can't be offended if someone doesn't want to have sex with you when you have your period as long as they are still happy to touch you," she says.
In fact, Ms Maxwell says many men actually don't understand what a period involves and what's possible sexually.
"As women, we know that having our period isn't dirty - there's nothing disgusting or unhygienic or revolting about it," she says.
"But women are really mysterious for men and I think it's fine to say, 'Look this is the situation I'm in but there's still plenty of other options for us. If you want to fool around, I'm keen for it'."