Go to Berghain which is above Lab for dancing or Panorama Bar which is also above Lab. Do not go to Lab just on the spur of the moment. It has the world's most notorious scat party and piss parties and so on and that might be too much. They do naked night there too, don't know if it is mixed or men only. I think the latter.
How to decide on whether to hit Berghain or Panorama? Is Honey Dijon or Jeff Mills in Panorama? Go to Panorama. Is Dr. Motte, Stacey Pullen, or Ricardo Villalobos playing at Berghain? Go to Berghain. As auncut states the dress code for Panorama is strict. You have to check it out before the party you want to go to, and with some, it is more complicated than others.
The other two wear black, all black nothing but black, nothing too fancy, the right accessories and don't smile at the doorman or talk to him. He picks you when he is ready. Do not speak loudly in English. He doesn't like people staring at phones either, but you can smoke cigarettes and pretend you're in Kraftwerk. For anyone not from Berlin this door is seemingly excruciating because nothing else like it exists in clubland anymore. But it is for a reason and the parties in the club are legendary as is the installation. Tresor is another of Berlin's techno monuments, but it is a little bangy for 30's gays I think.
Check these regular baths out, worth visiting at least one:
The Steamy Guide to Berlin's Naked Saunas
If you care for something terribly sleazy: Ficken 3000
There are also moving parties around the city every weekend you will find out about them in your travels.