Green’s Dictionary of Slang

teabag n.1

[rhy. sl. = slag n.1 (1)]

a general term of abuse, a worthless, irrelevant person.

[UK]J.J. Connolly Layer Cake 102: His outfit have sent him up to work out a deal with the smug Swell Mob and they’ve talked to him like he’s a fuckin teabag, a wanker.