"The idea came to me in a restaurant when I felt a bit sleepy after a meal," he told AFP.
"I thought it would be so nice to have place (for resting) and I started to think what it could be like."
After finding people liked his idea, Mast opened Naphouse in January after securing funding from the European Union's youth culture budget -- the cafe also doubles as an art gallery and an activities workshop for young people.
Customers seeking sleep or relaxation are given slippers, a pillow, a blanket and even a teddy bear before entering the blue coloured nap room, which has bean bags and doughnut-shaped mattresses on the floor.
"A lot of different kinds of people come here: students, teenagers, working people and a lot of mothers with babies," Mast said, adding his clients sleep there for about one-and-half hours on average.
Drowsy clientele can use the service for free, but some choose to make a donation to contribute the cafe's upkeep.
Now that he runs the Naphouse, however, Mast says he does not always have time to catch his own quick forty winks.
"I try to have a nap every day, but it is not always possible. Napping helps me to get a good night (sleep)," he said.
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