Please excuse the subject of this but I need some answers. Decker is now six months old and was neutered at around 9 weeks of age. Tonight we witnessed him mounting and for lack of a better term, humping Moxie. Is this normal? It's been four months since his neuter and he was so young that I can't believe he would have any testosterone lingering.

We've had this problem with Ripley over the years and the objects of his affections were an old Oscar the Grouch hand puppet and a blanket. We felt this may have been due to the vet leaving something during his neuter. Is that possible and if so could it be the case with Decker?

Rocky is my only other male and he has never done this as far as I know.