knobbling
The act of rubbing ones penis discreetly in public. Can be performed outside or inside the pants. Can be a short knobble or a longer rub and stroke. Different from masterbation as the intent is not to reach climax, but instead more like scratching or rubbing yourself lightly between pleasurable short term rubbing near or on the erogenous zone. Often performed on a couch, often while watching TV, usually in the company of men but not always.
Damien is knobbling while watching Fox Sports again, I can smell it from here.