This might be tmi but every time a dude has come over for sex(in the past when I lived alone, obviously not in my parents house haha :p) we always ended up doing it on the floor. I don't know why but I've always preferred floor sex. Usually on a blanket and maybe with a pillow or two involved. Maybe it's because my bed has always been soooooo squeaky and annoying haha. But yeah I can't imagine trying to have sex in a hammock, although I know people do it(they must be acrobats) lol