Bonobo Apes are one of very few animals - other than humans - who have been observed to have sex for pleasure rather than to satisfy the need for procreation
Bonobos are complete sex loons. They are on record as having lesbian / gay sex, frotting, orgies, oral sex etc. They're also meant to be the closest link to humans, if you buy into that.
Einstein - it was just my turn of phrase. What I meant was that this link may account for the fact that they have sex for pleasure. HomerSimpson; frotting is a more polite term for dry-humping!