My less than 1 year old dog is starting to hump my arm!

Whatever you do, do not and I repeat DO NOT mess with him sexually. At less than a year old his penis will be very sensitive. I've heard the stories over and over again and they all pretty much end up like this: "I fooled around with my <1 year old male dog. I didn't realize how sensitive his penis was. I was being gentle but I accidentally seriously hurt him. Now even as an adult my dog doesn't want me to touch his penis and he will whine/growl if I even get near it." It's a story that's been told 1,000 times.

Your best bet is to redirect his behavior towards something else.
 
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