A Bus Boner is an erection that one gets while riding the bus. It is usually caused by the combination of fatigue, warmth, and the vibrations of the vehicle. Similar occurrences have also been reported in mini-vans and tour boats.
Michael was afraid that when he stood up to get off at his stop everyone would see his bus boner.
A Buddy Boner is an erection that a man gets while hanging out with his male friends. It doesn't mean that he's gay; it just means that he's having a good time.
When Bill and Mark played poker together they each developed buddy boners. Man, were they ever having a good time.