Written as part of Polyamory, but got out of hand.

Rainbow Dash is very good friends with her friends. Very very good friends. Alas, she's a mare of many needs, and her desire for a stallion has gone unsated for a long time. Twilight Sparkle feels similarly enough to experiment.

Pinkie Pie is transformed into a stallion, with the physical capability to deliver sweet physical relief to both. But as both she and Dash soon find out, boning your friends is a surprisingly complex affair.

Side Note: There is nowhere near enough BerryDash art. Somebody should rectify this. I'm totally crushing on Berry right now.