So sorry to hear this dude,
I have had 2 dogs put down, one was a 19 year old mongrel we brought back from cyprus, i grew up with her (petra) she used to come skateboarding and windsurfing with me, out on my brothers and mine boards.
The other was a 15 year old irish setter (casey) again as i was older she used to come out with me in the drop top loving the wind lol.
mates used to take the mick asking who the red head was i had picked up.
Remember all the good times you had together mate, also think of him running around doing his favourite things but always watching over you.
RIP lucky