on it like a car bonnet

either a) for a police officer/detective/Sherlock Holmes or anyone along those lines in hot pursuit of either a of a criminal (usually a juvenile delinquent truating or in search of new adventure (unplanned) in the great outdoor wilderness. b) can also be used as a derogatory term for a couple who have sex outside in public (usually on the bonnet or hood of their own parked car). NB: my definition a) comes from the fact that some criminals aressted after a foot chase are brought back to the officer's patrol car/van, physically shoved onto the hood and then handcuffed. Also when people get lost in the wilderness while travelling by car, they might sit on the hood/bonnet of their car and think about what to do, sometimes waiting just long enough for an unplanned adventure to come and find them 9like a bear coming out of the wilderness to smell your vehicle). my definition b) refers to the fact that some couples do use the hood/bonnet of their car to have sex in public, think its okay, simply because its their car.