The act of repeatedly slapping one's member against the forehead or face of one's partner during foreplay.
I was Bobby knocking my girlfriend last night which turned her on immensely.
by Barrington_2007 August 20, 2007
I game or a prank younger people play which involves knocking on someones door and leaving before they answer
you wanna go bobby knocking later?
by Ian Handley September 14, 2006