The humping is not abnormal but you should train him to stop. My last male doberman would hump male dogs only- it was a dominance thing in a not so passive aggressive way, but yes everyone called him our gay dog.
My female GSD has actually taken to humping dogs she knows well be it male or female. We tell her off and when she tries to slide behind other dogs gets a firm eh eh. She gets it now and will generally abstain from the behavior, but done to the wrong dog Ozzy may be in for a serious bite since in doggy behavior it is a clear dominance play. Zoe began this with our lab first who is laid back and could care less, but now will do it to other familiar dogs and has been met by some not so happy to see her teeth. Teach him no now,lol though I would love to see a tiny pom going to town for some reason
