Give it some welly British Verb + object/complement informal
In British English, the noun welly, also wellie, short for wellington (boot), is used figuratively in the sense of force, power, frequently in the phrase to give it some welly
To apply more effort or strength to something
This is the last round, come on, give it some welly!
(Racing language) To increase fuel or power to an engine, as to a car by depressing the gas pedal.
The car is stucking in mud, let give it some welly!
Children or adults often say this phrase to get their friends to join in something, especially to jump into a swimming pool (pond, lake, etc.)
To try to achieve something or succeed in honour of somebody
To motivate someone to do something better, more quickly or more passionately
Used to encourage someone to accept an invitation to somewhere.
People often shout out the phrase to a person as encouragement or criticism, asks for more effort to be put into whatever he or she is doing. The phrase came about in 1970s. Welly or Wellie is a common British abbreviation for the term wellington boots, these being waterproof rubber boots named after the First Duke of Wellington.
(source image: internet)
The slang sense seems to have come about through mental links with various senses of boot or foot. One of the earliest appearances was in motor racing, in which the reference was putting the foot more firmly on the accelerator; another was in football, for a powerful kick. Wellies were, and still are, worn on working farms and would indeed be used when driving a tractor. It's credible then that 'give it welly' would be shouted at someone driving a tractor, hauling a load or driving out of the mud and it necessary then to push hard on the accelerator in order to get out of the mud or shift the load.
To say the same thing repeatedly
Ok, I get it! You sound like a broken record, seriously!