I had a long distance GF when I was in my 20s. We only saw each other about once a month so obviously we spent a fair amount our limited time together fucking because, 20 year olds.
So, we’re going at one Saturday afternoon and halfway through, I hear a group of guys on the other side of the bedroom wall making fake sex noises to mock us. Normally a pretty passive guy but in what might have been my most “establish dominance” moment to date, I just fucked her harder because she was a screamer and I knew she’d drown out any noise these dudes were making.
Anyway, that’s how we found out that the exterior walls of that apartment were just as thin as the interior walls.