Soon, I will be visiting Berlin with a gay friend. It would be nice to take him to some gay or gay friendly bars and clubs. We won't be trying to hook up, just enjoy the ambience and maybe a show.
We are both male and neither of us are young so we don't want very loud, high energy venues such as Techno.
I am not gay myself but I have visited many other gay bars and clubs with this friend and other friends. I know how to behave appropriately (basically just be a nice person) so, unless straights are forbidden, that should not be a problem.
Additions:
Venues do not need to be specifically gay; they may welcome a range of sexual orientations.
I am not expecting recommendations for specific bars and clubs but is there an area which we should explore?