knock it back 

take a drink of liquor in in one swallow, or very quickly

Marlowe woke up on the floor with a hangover and throbbing from a blow to the head. He poured half a tumbler of bourbon and knocked it back. Not a cure but would have to do for first aid.
(past tense of "knock it back")

knock it back by ray jr. December 10, 2009

knock it back 

A sexual phrase. Meaning during sex your head will be knocked back due to the amount of pleasure you are receiving.
Usually implied as oral sex

Damn she is fine, she can knock my shit back
Hell yeah last night she knocked it back
You can tell she'll knock it back for ya

knock it back by RiverBoY August 26, 2012