The practice of finding out which gambling market a friend or colleague has backed and then proceeding to copy the bet which subsequently loses. This custom is known as 'Spencering' whilst the person committing the offence can be referred to as a 'Spencerer'
Past tense: to be 'Spencered'
The 'Spencerer' is a wily animal and will often only join a bet when the odds have shifted into his or her favour. However, within moments of their participation, the wager can easily be observed going down the shitter.
Should one encounter a 'Spencerer' it is extremely advisable to maintain a cloud of secrecy. On no account should a 'Spencerer' be allowed to gain knowledge of ones wager.
I told Richard the horse I backed in the 3.20 at Aintree. It looked like a winner all the way until I realised I'd been Spencered by that cunt Richard! He is always Spencering my bets, the total dick!