Hi everybody
My puppy, Benji, it's just 4 months old and sometimes, when he's particularly excited, usually after a walk/run outside, he tries to hump me. I tried to ignore him at first with no success, so I started "punishing" him by closing him alone in a room for 30 seconds/1minute maximum and I think this is working.
Is there anything else I could do? Is it a normal behavior at such a young age?

Sorry for my English, it's not my native language. I hope I've been clear.

Humping is not always about sex for dogs.
Gary Landsberg, DVM, a veterinary behaviorist in Ontario, Canada, says mounting is common play behavior in puppies, and is even normal in the play of older dogs if it’s not taken to extremes. “You’ll often see one dog mount another, then a few minutes later they’ll switch off and the other dog will mount the first dog,” Landsberg says. “It’s a common play gesture.”
My 12 year old spayed female will hump our neutered 3 year old male when they are playing together. If you don't like this behavior then you can distract him with a different toy or game. I'm not sure that he will understand why you gave him a time out. The behavior may lessen after he is neutered.

I don't think it's particularly unusual although I haven't had that problem with my male Basenjis, but I didn't raise them from pups, either. I would just gently dissuade him from the behaviour and redirect him to something else. Unless he is persistent that may be all you need to do.

A firm NO, and ignore him. While it isn't sexual all the time, it can be dominance. Regardless of intent, no one wants a dog humping them. So try to say NO before he actually starts to hump, then walk off. He can understand that humping gets him ignored. Putting him in time out he probably doesn't understand.

Work on commands. at this age he should know sit, down, and needs to work on "leave it." Giving him training will keep his mind busy and help him see you as not a humping item.