Oh! the glory of it all.
When I was in the Navy in San Diego during WW2, I would take the bus to Modesto every liberty.
I would get horny and a hardon caused by the bus vibrations. I sure wasn't the only guy. I would sit in the back of the bus reserved for smokers. We would show our hardons to each other and mutually masturbate each other.
About 4 or 5 or 6 sailors or 'Braceros' Mexican farm workers would have a great time jacking off each other.
But I must caution you! Too much spunk puts out a musky semen odor and sometimes the passengers would smell it. One time late at nite with few sound asleep passengers onboard, the driver smelt our spunk. He stopped the bus at a small wayside stop and came back and joined us in a mutual jack off.
He was about 40 with a boy in the Navy and he really enjoyed jacking us younger guys.