Well you need today’s WotD ...
• noun Brit. Informal a foolish or inept person.
— ORIGIN originally a dialect word meaning something large of its kind: from PLONK1.
• verb 1 set down heavily or carelessly. 2 play unskilfully on a musical instrument.
• noun a sound as of something being set down heavily.
— ORIGIN imitative.]
The use of the word Plonker as a mild form of abuse was popularised by the British sitcom, Only Fools and Horses, mainly directed at the hapless Rodney Trotter by his older brother and wannabe wheeler-dealer, Del-Boy Trotter.
Derek ‘Del-Boy’ Trotter: “Don’t be a total plonker, Rodney”
Plonker had it’s heyday in the late 80s/early 90s but is still fairly popular today.
As you have realised now us Brits, as a nation, have our minds and sense of humour planted firmly in the toilet – therefore you will not be surprised to find out that plonker is also a euphemism for the male member (so to speak!).
Another variation on the theme would be:
you’re pulling my plonker - taking the mickey, poking fun at me