She holds up what at first could appear like a somewhat normal woman skin. You then notice the horns at its head, also it has absolutely massive breasts, though they're hanging down loosr as it's just a an empty skin for now.
"A cowgirl!" You exclaim.
"Yep," your girlfriend replies. She immediately starts putting it on, stepping into it one leg at a time.
The skins hangs off her. Your girlfriend is a skinny girl, so she doesn't fill its hips or any part of the skin. Though, pretty much no girls are curvy enough to fill this skin out.
Your girlfriend is almost done. She is standing in a sack of loose skin. That is until she zips it up. Immediately she changes. Legs fill out, leaving her an absurdly curvy rear. The once lifeless face started brimming with life, a pretty brunette with plush lips and bovine horns. The most noticeable thing was her breasts. They filled out in volume, reaching a size where her massive udders were large enough to conceal a decent portion of her stomach.
"M-moo," the cow girl let out.
"You still in there?" you asked her.
She nodded. "Yes." She squirmed. Her face was flushed. Her expression shifted, part discomfort part pleasure. "Can, um, you milk me, please."
"Of course." You replied. You moved closer. Her boobs are absolutely massive, not really something you can fit into your hands. You started by massaging them.
"Keep going, ah," she moaned. "Moo."
Drips of milk started leaking through her nipples. Then more. Soon, a stream of milk started flowing. Curious, you bend down and place your mouth at her teat and catch some of the stream. Her milk is sweet and creamy. You continue drinking for a bit, but then you stop, as while it's tasty, it's very filling, and you can only drunk so much until you'd probably get sick.
Then the stream of milks slowed down until it's just the occasional drop. Your girlfriend was sitting dazed in a pool of her own milk. What a waste. If you had a milking machine, you'd be able to store it instead of it spilling all over the floor.