A bar in Israel has come up with an unusual idea for happy hour discounts, which might even be the first of its kind in the world.

Anna Loulou, a bar in the Israeli city of Jaffa, is offering a 25% discount to menstruating women in an initiative named "Bloody Hour". The women behind the initiative, Moran Barir and Dana Etgar, believe women on their periods deserve "a favour".

Considering women menstruate for 25% of their lives, they deserve a discount of 25% on their drinks for at least a night, the two women said.

Through this initiative, they also want to raise awareness on menstruation and want people to talk about it more. "Since we come from that world, happy hour is an appropriate means for raising awareness. We want women to say, 'Hey, I'm on my period,' and for it to have a deeper and broader resonance, for it to be legitimate for women to talk about it.

"When it comes to men, I think these evenings will begin to normalize the situation­ – yes, women menstruate, and [men] should also ask questions and gather information about the subject. It's not only girl talk," Barir told Haaretz.

"Bloody Hour" will apply on Mondays, Tuesdays, Wednesdays and Saturdays.

"The whole idea is to give a discount, attention and a treat to someone, to say 'we recognise you, we are aware of the special situation you're in right now, and hey, we want to do you a favour,'" Barir said.

Women will not have to provide any kind of evidence to avail of the honour-based discount, she added.

The discount idea came to Barir at the bar itself when she ordered a wine for herself and the bartender forgot whether she had asked for red or white. "I told him simply, 'here's how you'll remember: I'm on my period, so bring me red'", she said.