I would not allow the humping; it is a sign of dominance and it is apparently ticking off your Beagle!
Ringo (my Westie) will not allow any dog to hump him; it's guaranteed to start a fight if they try.
Neutering will probably help (though female dogs do it too). For now, whenever your puppy starts that behavior - put him in a short 'time out' in another room for 2-3 minutes ~ away from the rest of the family. If you are consistent, he will get the picture pretty quickly.
__________________  Mommy to Lucy, Ringo, and Matthew |