just inserting some random info here:
sex isnt always defined as both people coming.
even a two inch long penis will "get the job done" if used properly
the bare, bare minimum to be able to penetrate a vagina would be somewhere along the lines of a half an inch.
even prepubecent boys can come. in fact, some even masterbate before they are able to produce sperm. they still come, they just dont produce any sperm. so when they come, its just seminal fluid. its a clear, semi-gooey liquid. that serves as nurishment(sp?) for the actual sperm.
im assuming the average size for a prepuscent boy (using my own childhood as the marker[so no pedophile jokes, please]) should be about maybe 2 1/2 to 3 inches erect. then again, i am just a little bit above average in size, so it could be a tiny bit less.
now, on the other side of the arguement:
considering what hes told us soo far, this had to have been either a teacher, a relative, or a friends mom, or a babysitter.
this had to have happened sometime when a parent was not around, like when the babysitter was there, between classes, while hanging out with a friend or family member.
this person is an obvious pedophile who should be locked up for being a child molesting creep.
finally, the term "losing your virginity" can fall under many contexts, its up to each of us to define when this happened to ourselves. this person obviously defines it as the first time he ever orgasmed. i personally define it as the first time i penetrated a girl. the next person in line might define it as the first time they got their partner to come. its a wide range that needs to be defined by you and you alone.