I sucked a twelve year old boy when i was ten. he made me do it at first but then i liked doing it any would go to him house and beg him to let me suck it. we would go into his room and i almost always took all my clothes off. he only pulled his pants down. but i wanted to be hitting naked little sex slave.
can't speak for others, but my best friend and i started sucking each other off when we were 8. we still manage to get together 3 or 4 weekends a year for massive suck and **** sessions.
not all, but a lot do. It is just a natural part of life. boys are curious, and are more sexually active than girls. i hope this answers your question. by the way, why do you want to know?