Well, the new top pick is in my now-partner's bed with her then wife passed out beside us. We both came really hard, too. And we were so lucky her ex didn't wake up because she kept a loaded shot-gun in the house.
Then, before that there was giving head in the back of a bus in broad daylight.
Before that, the the handjob in the washroom in the music conservatory.
And then, before that, there was the grope in the back of a church hall. (We were teens.)
BTW. I love being asked that question!