A sexual encounter, typically in public and typically between two males, wherein the couple frot (rub) against each other until one or both of the parties reach orgasm. Mutual hand Jobs are also acceptable, as long as the majority of the clothes stay on, the encounter happens in a secluded public place. Named after Boston, 'cause, really, what else are you gonna do there besides fuck and go to sporting events?
Gentleman A: I do say Wilberforce, you're looking rather dashing this evening
Gentleman B: Thank you Chauncey old bean, but it seems I have a rather urgent tumescence in my breeches, could I interest you in a Gentlemanly Bostonian Fuck?
Gentleman A: Why Wilberforce, that sounds smashing. Shall we rendezvous behind the azalea bushes? Wouldn't want the Mrs. to see, what?
Gentleman B: Topping, old bean, simply topping.