This is how I got my first hardon!
Watching tractors spin the rear treads
I used to go down to a form especially when it was wet and watch some ploughing
Even the accidental spinning made me horny
I would be cumming hand free in my pants if some dude put on purposeful spin session like this!!
There's more on his site but very old and take some fiinding. My farming background meant I was in amongst it and doing it all the time. Got the wheels spiing and got hard as often as I coiuld. Getting stuck and a lots of straining and revvig meant a sure shot in my pants
First time it happened I was watching a neighboiring farmer's son who got stuck with their tractor. I got hard and veery agitated. I went in to the barn and humped a bale of straw until I came. It was very violent.
https://www.youtube.com/watch?v=iQkc9KDXWWU is another
