Best of Both

Feeling the almost expert level of tongue work on her rear, Twilight knew she wouldn't be able to hold back her moans for much longer on account of her being a bit of an anal whore, the moans she would be letting out would seem strange and uncharacteristic of the activity considering she was still just jerking off her boyfriend. So with a sense of urgency that made Flash groan a little louder than he wanted to, Twilight threw her head forward, immediately deep-throating her boyfriend's cock and allowing herself to let out the moans of pleasure she was holding back. She knew she wasn't technically cheating on her boyfriend, but wasn't sure how he'd feel that she was about to be fucked in the ass by his Equestrian counterpart. Flash decided to do something that ordinarily he wouldn't do to a girl who was kind enough to blow him, but was betting on the fact that Twilight was clearly very eager to suck his cock and was simply enjoying having it in her mouth enough that she'd let it slide.

Flash grabbed onto Twilight's head with his cock still firmly lodged in her throat and held her there so that he could start thrusting back and forth, essentially using her face like a flesh light, his nuts slapping up against her chin. Twilight, despite the gagging sounds she made, held onto Flash's hips to signal that she was OK with what he was doing, which just made him go harder and faster than he was already going. Twilight struggled for breath, was choking and drooling uncontrollably, mascara stained tears ran down her cheeks and her eyes periodically rolled into the back of her head every now and then from the exertion of having a massive cock pounding the back wall of her throat. She was fucking loving it.

Back on the Equestrian side of the portal, Flash finally pulled away from Twilight's tight and twitching ass hole, it was time for him to squeeze his cock inside it. Flash reared back and mounted, hooking his hooves onto her wide hips as his erect cock bounced around underneath him, ready to penetrate the nearest hole. Twilight's height made finding the right place for his dick to go a bit problematic, he had to prod around for a bit to find the right hole instead of accidentally slipping into her pussy, which was difficult considering he was horny, impatient, had two heavily swollen cum-filled balls and was worried that if he didn't hit the mark soon enough that his body would start giving up and he'd lose his erection. Luckily as a member of the royal guard, precision was key in training and it didn't take him long before he felt his tip pressed against the soft wet pucker of Twilight's butt, time to get fucking. While finding the whole was tricky, entering it was a new level of difficult entirely, Flash pushed hard against Twilight's ass, his hips inching slowly forward as he attempt to get himself inside, but to no avail.

Refusing to give up, Flash pushed again once more, much harder than before and though Twilight's hole did stretch out a little, it still wasn't enough to allow his cock entry. Flash wasn't going to let this opportunity go to waste, so despite the trouble he was having went in for another try, hoping upon hope that he would have just enough power and muscle in his body to get himself inside this glorious ass that was basically being handed to him on a silver platter. With gritted teeth and scrunched up eyes, he groaned as he gave his hardest push yet, he maintained his level of force for several seconds until he was caught by surprise when the tight hole of Twilight's ass slid over his tip and obligingly allowed him to plunge his entire cock up to the hilt, swallowing his cock whole as his pelvis clapped up against her fat cushiony rear. Flash was in so deep he couldn't even make out the base of his dick, but at that moment he didn't care, he was too busy enjoying to ecstasy of his cock being surrounded by the gripping warmth of Twilight's jiggling purple booty.

Back in the human world, Twilight let out a muffled yelp as she suddenly felt the full length of a stallion dick roughly shoved up her ass, now fully stuffed at both ends of her body. Flash had brief moment of concern at the noise she made and paused his thrusting to look down at her "You OK babe?" Twilight looked up at Flash and nodded rapidly before tapping his hip with one of her hands to signal him to keep going. Satisfied that she was fine, he went back to fucking her face, hammering away at her sore and sensitive throat. It wasn't long before Twilight was moaning whorishly as she felt both versions of Flash eagerly pumping their dicks in and out of her slutty fuck holes, she couldn't wait for both of them to shoot their thick heavy loads inside her body, she wanted them to cum so much that their fluids would meet in the middle, she wanted to be a vessel created for the sole purpose of being a cum dumpster for the one and only... or rather, the two and only Flash Sentry. She just hoped she didn't faint in ecstasy before that happened and that neither of them found out about the existence of the other.