When someone says...
13 years ago
I lion therefore I lion!
They are mostly straight (especially in the furry fandom) what exactly does that mean??? o.O
FA+

in terms of the Kinsey scale, it's sitting at a 2.
mostly straight can also be used, as pointed out above, to indicate that the individual may only see themselves romantically attracted to the opposite gender in terms of relationships. Which doesn't stop them from participating in sexual flings or friendships with members of the same gender, it's more a comment on preference, and "ideal mate" as I read it.
25%- Gay
1. Mostly straight - 9/10 they'll go for the girl, but sometimes with the right guy...
2. Not interested - Usually provided if they are being hit on by a member of the same gender.
3. Straight but desperate - Getting some ass is better than none, right?
4. Closeted - Claim to mostly like girls but always end up with guys
5. Actually just straight - But wanting to fit in
6. Straight, but really into this one thing - They have an intense kink, and they don't care what gender is attached to it. But for basic sex they like girls.
7. Weirdo - They're giving that answer to hide the fact that they only get off to rubbing doorknobs on their knees.
8. Asexual in denial - Similar to 5 in why they say it.
9. Inexperienced - They're ambivalent and haven't tried all the fruits of the world.
10. Some sort of wizard - They're undercover spies from the future here to steal your socks. And their answer is part of the plan to do just that!
In my definition, it's a mix between suppressed bi and unsure of what I'm looking for...