I really do appreciate your input! Hopefully I don't come across as argumentative, but I guess I should have been more clear in my post that my personal definition of sex is pretty conservative, which is why I am not counting oral. I would disagree that my penetration distinction is arbitrary. What counts and what doesn't count as sex should be subjective and mutually agreed upon by those involved.

With that being said, I would highly doubt anyone from my past that I have gone down on or has given me a blowjob would ever say "oh yeah, I've had sex with caffeinatedpinapple!" Unless vaginal or anal penetration is involved, I can't reasonably say that I have had sex with that person. However, sex could have a totally different definition between two other people, and that's perfectly fine!