I was probably about 14-15 when it happened with no intention of it. My parents used to have a small farm/more like plantation, with no animals just 2 dogs to look after the farm when we weren’t there. It was summer break and I was the one in charge to be there looking after everything, nothing to do there so I was doing what we all do alone, took my clothes off and started jerking off, our St. Bernard came to me, I didn’t stop, but he came really close and started to lick my cock, which felt great, with that huge tonge he was all around, even started to lick my asshole, finished me so fast, after that I was going to him when I got a hard one, been doing it for a few days when I noticed he got hard as well while he was licking me, so slowly touched him, he was huge, giving him only handjob first, took a few times to use my mouth but he seemed happy about it