Very odd behaviour

Rocky is 4 years old.
We have just returned from a weeks holiday and Rocky stayed with my parents.
On being reunited he will not leave me alone. He is constantly licking me and trying to hump me. He does this every year and it usually last 2 days before he settles down.
He doesn't do it to the wife or kids. He is relentless and my current defence is a to spray water at him if he doesn't do as he is told.
Has anyone else experienced this behaviour? (concerning dogs)

Oh please don't spray him! He's clearly having issues with you leaving him, creating a worry associated with you returning may make his behaviour worse or lead him to find another, equally undesirable behaviour to express himself.

Instead of focussing on what he shouldn't do, I would instead give (teach in advance) something that will give him an outlet for his reunite joys but that is incompatible with humping.

I'd try asking (not telling) him to do things that you can praise him for. You could teach him different tricks in advance like getting a special toy to play with, doing high fives, rolling over, etc. The key is giving him things to do that will give him a reward that he rates more highly than your leg.

If he finds even that difficult, you could get someone else to pop him on a line just so he can't reach you, encourage him to settle down, the reward /praise that.

Id also suggest everyone keeps excitement and energy as low as possible as that will in all probability add to his.

Please excuse my initial reaction to the spraying, I'd hate it if someone did that to me.

I agree that association with something really fun could be the answer. Does he like ragging toys ? I'd use something like that to reinforce that return is fun

As the day has gone on he has begun to settle down. So no need for the spray anymore.
I did try earlier diverting his attention with his no1 passion.....the tennis ball! Even that did not detract him from focusing on me.
Basically nothing would work. He wouldn't eat, he wasn't interested in anyone else and he wouldn't leave my side. A long walk helped, then washing a couple of cars and me generally keeping busy kept him at bay.
As I said, he's settled down now and returning to normal but the behaviour is very odd.

why spay your dog have you ever thought he misses you when your away ? he sees you as the alfa male. if my boy didn't greet me with all the viger he could muster i would think something was wrong he's like a shadow but i wouldn't have it any other way

I'm glad he's settling again.

Rather than distractions, I mean trained behaviours that you establish well before you go away, something he knows he has to do to get your attention, which is probably what he's after.

Sorry, not convinced by the alpha male theory. I think he just loves you and is excited you're back, but maybe a little too much!

My thoughts are that when you get back no matter where he is, take him out immediately. Don't get to the point he gets too excited. Literally phone and say "im at the door, put his lead on" and you open the door grab the lead and start walking.