Jas was neutered at 6 months. He's now 22 months. Just recently, he has got a bit humpy with one of his doggy mates (gets the wrong end, though) and just now he tried to hump the puppy with hilarious results (The puppy is barely 6 inches high, so in fact he was just thrusting across the carpet in a tribute to 'The Full Monty'). Is this linked to anxiety? He always looks vaguely unsure before the humping. For example, he adores his doggy mate, goes bonkers with joy when he sees him...and then seems to not know how to interact, panics, and humps his face. Luckily, doggy mate is bombproof and merely huffs a bit as I drag a confused spaniel off his head. Just now, with the puppy, he was laying in his bed and the pup was running up and barking at him, play bowing, and generally trying to get him to play. Jas leapt up, play bowed, and then did his air thrusting over the puppy's head. The puppy hid behind my legs. It took Jas several minutes to notice.