I guess this happened during my last year at secondary school. I had sat next to the same guy in music lessons for a while and one day, and I am not sure how it started, we would hit each other in the groin, not hard but a gentle tap. From there it progressed to squeezing. Of course as things started to progress we both got hard and took turns to squeeze each others hard cock.
This must have happened for quite a few weeks before we both forgot about the hitting and just got on with the squeezing, we would take turns to squeeze the end of each others cock, always through our trousers, we would squeeze the tip of each others cock through our trousers until finally it happened, and I think it was me first, we came in our pants. It whiled away an otherwise boring lesson, many is the day I went out of that lesson with cum in my pants and I know he did too.
It never went any further than this, I am a married man with no other bi experience other than this and I know he is married too. I don't know if he has had any other bi fun since then. I have to admit I have wanked many times thinking about us squeezing each others cock until we came in our pants and wondered if Trevor has done the same.