wow this is interesting:
http://www.mymessybedroom.com/columnshow.asp?id=216
"It's great," laughs J, "If I'm having sex and get sore in one vagina, we can switch to the other."
"What other guy can have sex with two vaginas and remain monogamous," he laughs.
Though J's boyfriend admits he usually defaults to J, the slightly larger of the two canals.