The art of getting your cock and slapping it on your partners forehead before they wake up. Sometimes done before a blow job but less popular
cock knocking = Oli cock knocked Ben before a BJ, Ben was not amused
Cock knocking involves two males. One male has "trained" or "stretched" his penis hole, commonly using house hold objects such as markers and progressing to larger items, etc.
The second male inserts his erect penis into the urethra of the male with the "stretched" hole and they proceed to have penis to penis sexual relations. often resulting in disturbing infections.
"Bob and ted reached a point in their relationship where they felt it necessary to start cock knocking."
"Ed f*cked James' pee hole"