Actually, no. I didn’t mean that orgasm is necessary to it being “sex” (although I see how it came across that way). I was just highlighting that penetration is not necessary to it being “sex”.
Actually, this definition works for me.
Since we can’t seem to come up with (ha!) a catch-all definition, we’ll have to go through the possible scenarios one-by-one, and debate the sex-iness of each.
Yeah, but you have to be in the same room and touch each other at least occasionally. Phone sex or cybersex isn’t really sex. Well, it would be enough sex that if you did it while married it would be adulterous, but not enough sex that if you did it while single you could tell your friends you had sex with the other person.
I usually go by the “penetration” school of thought. I put my number at how many people I’ve actually had intercourse with. Still, I can see how it would make sense to count oral sex. Either way, my number remains the same.
I guess I think of “sex” as penetration because I think of sex as a means of reproduction, and you aren’t making babies through blowjobs.
Any genital contact is sex, to me. That’s what I think of it as, and that’s what I report.
…and let’s not forget it has to be in the missionary position!
I go by penetration. Blow jobs and masturbation doesn’t really affect much- if it didn’t happen you would have had a crummier night but thats the only real effect. Penetration bring drastically increased STD risk, pregnancy, and changes to the cervix. It’s a different animal.
::unpacks bags::
It really depends on who is asking and why. For instance, Dr. Morin’s Sexual Excitement Survey asks:
http://www.sexuality.org/l/sex/morinses.html
This is a broad definition. If you limit it to PIV sex, you are excluding quite a bit, but in some circumstances PIV sex is what the questioner really needs to know. For instance, a Kinsey 6 lesbian does not need birth control, but some doctors might approach the subject by asking if she is having sex. E.g., http://www.avert.org/faqcontra.htm
So when somebody asks me, I ask what they mean.
So if a man is found dead, with a broken neck and his balls resting on his lips, was it sex or masturbation?
All this sex / bj talk reminds me of my fave quote regarding the Clinton/Lewinsky impeachment debacle:
@*#^$, knew I forgot something. Let’s ammend it to "As for my definition of sex; any physical act involving more then one person where the intent is for at least one person involved to receive sexual gratification is sex.
Peace - DESK
Okay. You start! 
Blow jobs *are *penetration, with a risk of disease transmission. It’s a smaller risk than vaginal or anal intercourse, but not nonexistant. Hell, on any given day, I’m far more likely to have a small open wound in my mouth than in my vagina.
Mutual masturbation = sex or no? (FWIW, I say yes.)
Mutual masturbation, to me, is sex. More then one person is physically present and physically involved and it’s for sexual gratification.
Peace - DESK
Look, oral sex is sex, otherwise gay men and lesbians would be virgins. I don’t think “Honey, I didn’t have sex with him, I just sucked his cock until he came in my mouth!” would fly as an excuse if I tried saying it to my wife. And oral sex IS penetration.
Yeah, I’ll go along with the idea that oral sex is a bit “lighter” than intercourse or anal sex, but it’s still sex, that’s why they call it oral sex instead of oral-something-other-than-sex.
Bill Clinton is member of the SDMB!