I used to work with a guy, I'll call him JD (for John Doe). JD was gay. He wasn't overtly gay, he wasn't "in your face" gay. In fact nobody really knew unless he told them, or used words like "scandalous." JD was also my smoking buddy, and he spent a lot of hours hiding out in my office to avoid work.
One day, after it became common knowledge that JD was gay, we were outside on our smoke break with another person from the office. We were all just chatting, nothing serious. JD was talking about his boyfriend. One of us asked JD why he and his boyfriend didn't live together. JD said that they had tried that, but that being together all the time wasn't good for them. We made the comment that they seemed to get along to us. He said, "Yes, but when we live together and up each other's ass all the time we always end up fighting."
I sat there quietly for a minute, but then the inappropriate giggles started. I tried so hard to suppress it, my face was turning red, I was studying the leaves on the magnolia tree, I was thinking about soccer... nothing worked. The other person who was out there saw the expression on my face and immediately knew what the problem was. She tried to distract JD so he wouldn't look my direction and see the pain I was in. I finally just told them I had to get back to work and ran inside.
To this day I get the giggles over the "up each other's ass" comment.