They will only go at night, often when their partners are away, for cheap and anonymous sex.Mark also says that saunas are “dying a death” – and that adult cinemas are becoming ever more popular with both gay and straight people.

“They don’t talk to you,” he says, “so once you’re over 30 you’re past it as far as they’re concerned.” The Dock is a home away from home for Mark: an intimate, comfortable place to meet other men. The Dock sauna has people who come in at the weekend and come up from down the country.

In that respect it’s good.” Like Kevin, Mark says that a lot of the men he encounters in saunas, particularly at weekends, are closeted.

According to the Pew Research Center, the overwhelming majority of Americans suggest that online dating is a good way to meet people.

Interestingly, more than 15% of adults say that they have used either mobile dating apps or an online dating site at least once in the past.

Mark, who is 48, and also goes to saunas abroad, agrees that the Dock tends to be visited mainly by older men.

But this is its appeal for him; he says the Boilerhouse is “full of 18- to 25-year-olds that think they’re God’s gift to mankind”.After that I end the night on a high.” Saunas have a reputation for being used mostly by older men, but Kevin says this has changed.“When I first went there I thought I was the youngest.Dublin is home to two of them: the Boilerhouse and the Dock, places where huge numbers of gay and bisexual men of all ages, forgoing smartphone technology, still go to have sex.Kevin, who is 32, has been going to the Boilerhouse several times a year since 2012.I went there on New Year’s Eve and had a fantastic time.