Hi,
As far as orgasms go for me.... Well as I approach the finish line or so to speak I can feel an intense feeling building in my cock.... As I start cuming my cock pulsates and each pulse feels incredible along with shooting a long strand of cum out of course.
To be honest though I was happy to explain what it is like for me but it is a really personal thing.... I've asked mates and while it seems that male orgasms are all fairly similar there are slight differences....
My advice, tell your friend to take the hands on approach to seeing what it's like rather then reading others experiences.
"In the quiet words of the Virgin Mary... come again?" - Brick Top, Snatch.