No, not kidding. Get a vibrating device that you can slip into a pair of panties with a cordless remote control and have a solo sex session wherever—on your morning commute, in your cubical at work (if your office din is louder than a vibrator), the list goes on.
To cover up the inevitable in-public O face, take a bite of food or sip of a drink at the big moment and exclaim ‘oh!’ about how good it tastes, er, feels. Or, if you’re actually caught in the act, just tell the person, ‘I’m just squirming around because I’ve gotta pee.” Can’t argue with that.