>Her brain is just not registering any sign that you're interested.
>Years ago she resigned to the fact that no stallion would ever want her, and she wouldn't go so low as to suck massive clit to get into a pre-existing herd. 
>Not only is she dense but signs of human interest are completely alien to ponies. 
>Reaching out to touch her.
>Prolonged eye contact coupled with forward facing eyes.
>Turning you body posture to face her direction and leaning in.
>Constant baring of teeth in a goofy smile.
>That thing most guys do where they try to make themselves appear bigger and more imposing, and subconsciously lowering their voice.
>These only send, "Ohh shit, that creature is going to eat me" vibes even though she knows you're a big teddy bear. 
>And the more you ham it on the more unsettling it is than sexy for the smol pone.
>And in return her reciprocation is in the negatives. 
>Instinctively backing up if you don't warn you want to pet her first.
>Your prolonged eye contact makes her look down and away until you ease up.
>She doesn't smile at you, in fact all the ponies make a guttural nicker instead of laughing. And they way they smile just feels different, not even disingenuous, just outright inhuman.

Adding onto this with a short oneshot.

>It's Saturday, the usual hangout night.
>And like most hangout nights you're in a shoddy bar in the ass end of Manehattan.
>Like, This bar is literally called the Ass End.
>You get a few drinks into you and your mate.
>The plan is to try and hook with another mare, just for the night.
>Maybe even play wingman and screen some stallion thots as an apology to your friend.
>God, you feel like a fucking cuck.
>But you absolutely need to cure oneitis syndrome for your friend, or she's not going to be your friend much longer. 
>The poor mare has been shooting down and deflecting every single sign that you're interested.
>You're socially awkward but even you know the motions girls make when their creepy guy sense is buzzing.
>At least she's still a bro and makes an effort to plan half the outings you do, and even go to them to shoot the shit.
>Knocking back another of their strongest brew to get your buzz a little more buzzy, You think now's as good a time as any.
>You turn away from her and swivel around in your tiny horse stool and start eyeing the bar like a hawk.
>You're almost sure the gender roles are reversed, so talking a mare up to get to her tail hole will be much easier.
>In your peripheral you see both your mate's ears rotate towards you, and she slowly turns your direction, but not fully.
"Yeah?" you ask, not turning your attention to her.
>Gone is your sharp, suave, lower tone of speaking. 
>Now that you think about it, that whole song and dance was plain cringy.

"Anon... I'm sorry."
>Cocking your head, you swivel back around to face her and look her in the eyes.
>Again she looks down and away and scoots to the edge of her bar stool.
"There's nothing to be sorry about. Wasn't cool of me to keep hitting on you like that when we have this great thing going already."
>"Hitting on me? I thought you were being a stallion and didn't want to say why you were mad. Wait, are you upset because-"
>You hold your hand up making her flinch enough to fall out of her seat.
>Luckily your reflexes are sharp from years of playing pocket-pull, and you easily grab her, sitting her upright. 
>You instinctively pat her wither's down, making sure she's fine.
>Instead of grateful she looks even more horrified at your ministrations. 
>Shit, there's definitely been some kind of miscommunication.
>You stare deep in her eyes.
"First of all, I'm not, nor have ever been upset with you. Second, why would you ever think I'd be-"
>"Sir?"
>You turn to see the bouncer, a lean looking donkey mare.
>"Sir, I'm going to have to ask you to leave."
>you turn to face her and put your arms up in submission, which makes her jump.
"Wait, wha-"
>You protest is cut short when the bouncer nips the leg of your pants and pulls you off the seat, you hitting the ground with an audible thud that makes the bar go silent.

"I really think this is some kind of misunderstanding."
>The donkey just snorts, and doesn't stop until you're pulled out into the street.
>"You're lucky I don't have the heart to hit such a cute colt, even if he does have a wild streak." She smirks at you and heads back in slamming the door in your face.
>...
>What?
>Your pal, comes rushing out the door, a worried look in her eyes.
>"Anon, Buddy, are you okay?"
"Yeah, yeah," you say, sitting up to move the shoulder you landed, a bit stiff but no damage. "Fuck was that about?"
>"You're askin' me? You're great, Anon. But i've been trying to figure you out ever since we met."
"Figure me out? I just got thrown out of a bar by an equine a third of my size for talking with my friend." You hop to your feet and pace back and forth in frustration. 
"Just-" You take a breath to calm down. "What were you even sorry about."
>Your friend snorts, and sits her rump down on the curb. 
>"I don't know, 'S just what you gotta say to stallions when you don't know why they're upset with you."
"You're a big help."
>"Shut up, Anon."
>Sighing, you sit down on the curb next to her, and sit for a while, just enjoying each other's company.
>Aside from the odd patron, stumbling out of the bar, it's relatively quiet and peaceful despite being a "bad neighborhood."
>At some point in the night, the two of you start to get on home. Yours since it's closer, and you can spot a few more drinks before you call it an unsuccessful night.

>...Screw it, you're letting the alcohol talk.
"Look, I'm going to be real with you right now." You turn towards her, and this time she anxiously meets your gaze. "Obviously my- whatever I'm doing- puts ponies off so I'm going to go ahead and say it."
>"Yes?" she says cautiously, swishing her tail.
"I'm really fucking blueballed and could use a good shag, fuck, roll in the hay, whatever you ponies call it. And I'd like you to be my girl."
>Fuck, maybe you should have proclaimed your feelings of love and adoration you’ve nurtured over the last few months a little more eloquently than that.
>She looks surprised, but not outright horrified like a human chick would be right about now.
>"Sure."
"What? Really? Just like that?"
>"Anon, I'm not a dyke. And we get along so it shouldn't be weird... right?"
"Right. Okay." You say, running your hand through your hair, sporting the biggest fucking grin.
>20 minutes later.
>She kicks at you and whinnies in fear when you try to roll her over to her back to kiss and nip at her neck.
>It seems the only action you're getting tonight's with a bag of ice.
>And you owe you pal- sorry, marefriend- 15 bits for the tab.
>Yeah, this whole relationship is going to need fine tuning.