I would think that any insertion into any bodily orifice which results in an orgasm would have to count as a run scored.
Anal is at least a homerun, maybe like extra innings or something? Even silenus left that one alone!
Aren’t we getting away from the idea of the base analogy? It’s shorthand for the majority, are that many kids having threesomes and getting anal?
I have no idea how homosexual sex fits in, or even if it does. Certainly makes better sense for the oral is a homerun theory, and after that I’m lost.
Thinking back to when I was a teenager (when the air was clean and sex was dirty) I would agree pretty much with Silenus
Oral sex was for sure an in the park home run. 
Anal would have been winning the divisional championship
A threesome would have been a sweep of the world’s series.
FTR I never won the divisional championship in high school. Don’t ask about the World’s Series. 
I was woefully undereducated about this in high school (I would have graduated in 2003, FTR). But the way my college roommate explained it to me definately left oral sex in a very gray area. She described it as the f-system: french, feel, finger, fuck. I’m really not sure were oral should go, as most of my generation insists it isn’t really sex and I tend to agree with them, although in straight chronological order, it seems for many people, oral sex may indeed come after regular sex.
As for anal sex, I’m not sure people in middle and high school (where this grand euphimism must have been created) talk about that as openly as other sex acts, because even in a straight relationship, it leaves for speculation and that age group has to be the most homophobic I have run across.
I have to agree with the 4F’s (graduting class of 2002 FTR). Personally i think oral sex is third base or maybe kind of like stealing home as only one person orgasims.
In my experiance though the rules, (as with most things, thats a different rant) are different between men and women. For me i think that going down is an intermediate step preceding sex, something to be included into foreplay. Where as for women it comes after sex.
But here is where i draw the line. Homerun = Sex
Sex= Rusian rulette. If there isn’t the chance no matter how remote, (excepting of course permanant surgical procedures) of the woman getting pregnant (or similare act for same sex couples if one were to assume the other person were of the opposite gender) then it’s not sex.
Phoenix
P.S. This give me a thought, i’m going to start a side thread about opinions on Oral sex.
By the base system, I would imagine.
You’re trying to stretch something made up by horny white adolescents (from Alabama!) 60 years ago to cover a range of possibilities that wouldn’t have occured to them. So I wouldn’t say lesbian fingering or anal intercourse is so much “third and fourth base” respectively, but rather outside the confines of the system.
And really, lesbian sex would much more be hockey. Pfffff. 
In my experience growing up in high school (1989-1993), oral sex was definitely not the same as a homerun.