Lambering a dude is to give him a reach aroundwhile sticking a finger up his anus,
pretty much like a
rusty trombone except the blowing in the anus part is replaced by fingering the anus. Much like a
rusty trombone, lambering produces a specific vocal music, made by the recipient, somewhat ressembling a baby sheep's bleathing, or "baaing", namely bleats, grunts, rumbles and snorts.