There have been a couple of events, it depends on what someone considers naughty (sockless in bowling shoes definitely is
)
Out of my memory:
Fingering my GF while she's driving in her convertible. During a stop at a traffic light a druck driver caught us through the open roof.
Fucking my girlfriend bent over the table in our garden house, while our guest went for a pee brake. He was waiting outside until finished (unfortunately)
Having wild and noisy sex w/ my GF in the morning after a party. We forgot that my sister was staying over and sleeping on the floor at the foot of our bed. She woke up during our lovemaking but didn't dare to speak up or stop us.
During a BBQ party: Having sex in the woods, directly besides an anthill. not really naughty but U can imagine...
Receiving a BJ from my former best buddy after he committed that he wanted me for a long time. We had a long discussion about his confession, a lot of whisky and finally went in the backyard behind a bush where he blew me off. It was just meters away from his bed room with his sleeping wife. The tiny bush was hardly covering us from being caught and the moans could easily be heard.