...so, an older male may provide oral sex to a young male...

Highly recommended reading for those who still have any doubts regarding the equality of the sexes.  It's a stroll through the differences between the sexes in taxonomic groups, starting from the mammals, progressing through smaller and smaller groups, more and more related to us, and ending with us!  Fascinating!

Uh, I know bonobos are apes, not monkeys.