You don't say whether your GP is male or female, or whether he/she objects. I would consider it cause for concern if the GP is upset by it, if your poodle tries the same behaviour with other dogs who are upset by it, or if it upsets you. For dogs it is just another way of filling the time, I suspect. At 160 lbs, no doubt your GP is more than capable of telling him off - if you want to change the habit, distraction and reward for stopping are probably the best methods.
More on humping here:
The Down & Dirty on Humping: Sex, Status, and Beyond | Dog Star Daily
My two females get hooked on humping games when one of them is in season - I rather discourage it, as I have visitors who find it embarrassing. As soon as their hormones calm down, they forget all about it till next time.