@James Rye  
I fully agree! While I do enjoy a nice packor of ships in a fanfic, 3 lesbian pairings of the mane six, is to much for my taste… not to mention the very unlikely and thin probability that all of them share this kind of affection (which makes the whole scenario even more unreal). Let’s suppose the gender ratio for f/m in ponyville is about 1:4 (there are much more females shown in the actual series), it would only be natural to assume that lesbian relations are common, on terms with the locals, but NOT exorbitantly spread.  
The only exception to this rule would be a severe case of the “estrus” for every of the mane six at the same time, but we don’t know if thiskind of cycle even exists for them. Furthermore, here it is to consider that every shipping action would be to blame on their “carnal passion” (In other words, hornyness triumphes over sincere feelings).

@Princess♠Molestia
 
I hope not, never was a huge fan of “all six mane6 are gay for each other”. Not saying that I’m NOT a fan of it, but I’ve rarely read or seen stuff of all of them being gay in 3 ships which didn’t made my eyes roll till I almost saw my brain inside.
 
Also poor Spikey-Wikey if Rare were gay. Then he really has no chance with the age gap, the different species thingie AND the prefered sex of his beloved Rare. XD
 
Who knows, maybe Shy is married to Big Mac already in this universe?

@Jadefire
 
I’d say so, yes

@Ertinax  
That would be Twilight and Rainbow, right?

One of these three mares is Bibliosexual.  
Another is merely Bibliocurious.

@gittonsxv  
I’m guessing since there are other sapient species there (dragons, gryphons, etc), maybe being into them is considered a different kind of sexuality.
 
Like, being into male dragons is different than being into male ponies, etc.

@gittonsxv  
There are at least 5 recognized orientations, though the last 2, Pansexual and Asexual, are controversial even by sexuality standards.

Except you’re all carpetmunchers by sheer force of habit.

can something be broad with like 3 options?

Aka She’s gay, they’re gay, everyone she has ever come into contact is gay.