Yep! Not to worry ... as embarrassing as it is to us humans, they don't suffer the same "moral constraints" we do. As far as I can figure out, "if it feels good, do it!"
My male has a favorite circular bed. You can almost set the clock by him: 8:30 every night he trots back to my bedroom, has his way with the bed, then comes back out to the living room to crash for a while
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Some dogs are downright embarrassing, humping anything and everything (those are usually the ones that haven't been neutered yet). Some have a favorite toy or object. In any event, it's normal, so don't worry about it.