Put that milk to good use.

Kathryn wastes no time in going to work on my tits again, and before long her eyes are glowing so bright that I can see it through her closed eyelids.

"Orgasm."

Kathryn cries out in pleasure, jerking her face away from my chest. A last squirt of milk sails through the air and lands on my neck.

"You're my girlfriend, and I'm yours."

"I'm your girlfriend, and you're mine." I could swear the glow in her eyes was heart-shaped for a moment.

"Now lick this up." I point at my neck. "And then let's get up. We have work in two hours and I have a plan."

"You have a plan." As Kathryn cleans the residual milk from my neck, she starts moaning and clutching her boobs. Her starship-covered blouse is stretching out a bit.

"Interesting. Looks like my milk has more than one effect."

"Your milk has more than one effect."

"Stop repeating everything I say, this is getting annoying!"

"I will st-- Sorry, I didn't even realize I was doing that." Kathryn lifts herself off of me and stands up from the bed. "So what's your plan? More shenanigans at work?"

"You bet. Do you have milk cartons in the fridge?"

Her eyes light up. "That's an amazing idea! Wait a second, I'll be right back!"

I lift myself off the bed and try to pull the cups of my corset over my breasts. They're uncomfortably tight, and my nipples don't want to let themselves get tucked in. "Hey Jen, can I have my phone? I want to adjust something."

The succubus on my bed gives me a You're no fun kind of pout, taps out a last purchase and hands me back my phone. Its back is red now, and the camera bump has sprouted two stylish devil horns. I can't wait to get myself all of the possible upgrades! Wait, didn't I just want to fix my top? I look through the app's purchase history.

[Succubus Special] Harem Builder - 20 Gems - User tries everything in her power to get as many Girls as possible

[Succubus Special] Impulse Buyer - 10 Gems - User actively looks for things to buy in the Custom Girls! app as long as there are Gems available

Jen speaks up in the background. "It looks like you don't need me anymore right now. It's been fun playing with you two, see you later!" She blows me a kiss that I can feel burning below my skirt, then vanishes in a cloud of purple sparks.

She got me good. At least she didn't get me anything I don't want. Wait, does that make sense? The app made me want those things. But now I don't want to not want them! Aaarrgh!

Resolving not to think about it too much, I open the Clothing tab and buy The Breast Possible Fit for a discounted 7 gems (down from 9 due to my BreastMaster achievement). I immediately feel relief as my corset starts to remold and re-lace itself to accommodate my milky growth. It even grows two hidden zippers for easy nipple access, like a nursing bra.

The next thing I want to know from the app is what modifications I can get for my Mystery Milk. Annoyingly, it just says Find out more about this customization to unlock modifications. I guess we'll have to play around with it some more.

Well, I still have 33 Gems burning a hole in my pocket, so it's time to buy some practical stuff for myself. There's Quick Drying for 3 Gems, that's nice and cheap and it came in really handy on Kathryn after the shower earlier. Self-cleaning Clothes is another one of these, only 6 Gems and super nice to have. I buy that for Kathryn as well, it's even cheaper on her since she's my Favorite Girl.

Speaking of which, there's a Ding from my phone.

Achievement! That's My Girl! Level 3 - Make 20 purchases on the same Girl! - +20 Gems, discount increased to -40%

Up to 40 Gems again, I wonder if there are any large purchases I can make for Kathryn's boobs. It sure felt nice to have mine sucked, maybe I can do that for her. And I could stand to drink some milk 'from the tap' myself. Searching for Lact- on Kathryn's page quickly brings up some options.

Lactation fetish - (30) 12 Gems

Lactates when aroused - (60) 24 Gems

Lactates on command - (90) 36 Gems

HotKey - Lactate - (80) 32 Gems

Lactation modifier - Flavored Milk - (5-50) 2-20 Gems

The discounts on breast-related stuff for Kathryn are slowly but surely getting ridiculous. I remember what she said about not wanting the inconvenience even if she finds the concept of milky tits hot, and go with buying the HotKey.

DING!

Achievement! BreastMaster Level 3 - Make 20 breast-related customizations - +20 Gems, discount increased to -30%

It's like the succubi don't want me to run out of gems, but at the same they want me to spend them all!

As I'm wrestling with this conundrum, Kathryn comes back from the kitchen, carrying two freshly-empty milk cartons. "Wanna fill those up? Oh, where did Jen go?"

"She left after saddling me with some BS customizations. Also look, I bought some things for you!" I set my phone down on my lap for her to read while I unzip the front of my corset's cups.

"Wow, you're on a real spending spree - oh, I understand why", she adds after seeing what Jen did to me. "Harem Builder, really? As if you haven't caught enough Girls at work already! Well, at least I can help you getting more", she smiles and starts kneading my left teat. Slowly but steadily, milk is starting to trickle into the cardboard container. It feels amazing.

"I think it might go faster if you use your mouth." My breathing tenses. As she bows down and kisses the top of my breast, I let out a moan, along with much more milk. "Oooohhhh, looks like you don't even need to suck my nipple. You can just kAAAaaaahhhhhhhh!" She just blew a raspberry on my tit.

Several milking-induced orgasms later, we have two liters of magical milk in innocent looking packaging. Perfect for the office fridge next to the coffee machine. Speaking of, it's time to leave for our afternoon shift.