CJ is only 8 weeks and is mounting everything that doesn't move, bite or he wants to consume. This seems very young for this behavior. Is this normal? What can we do to protect ourselves (pun intended)?
I'm a fan of ignoring all the "bad" (aka unwanted) behavior that isn't harmful. All this harms is human dignity. The pup will outgrow the behavior. You might distract him by asking for an incompatable behavior. (Sit, look, come, down all are good and he will learn these soon.) And rewarding it. Hopefully he won't get humping tied into the chain as in "hump, obey command, get reward.."
This is part of puppy play behavior and even female pups display this way.
Fortunately, the only thing Keefer ever humped was Dena. He was about 1/4 her size at the time, so she could just stand up and dump him off. If she didn't do that right away (she was pretty patient with him!) I'd tell him "off" and remove him by his collar. In our house "off" means get off whatever you're on, so it works if they jump up on me, or the couch, or in Keef's case, his sister.