My Neo started humping his blankie when he was just a baby! Very precocious! The vet said that it actually is beneficial to them as it helps to "seat" the testes so that there is less of a chance of them to be undecended (thus making it more of a difficult neuter). Yes, it is VERY annoying if they're humping inapropriately, and should be discouraged. I just got Neo a stuffed "Phucky" duck that became his object of affection. Even now, at almost 2 he will still take "private time", usually after a full belly in the PM. He really reminds me of a teenage boy in that regard, lol!
