In the palm of her hand, quite literally.

You groan hoarsely as you are quickly brought to climax, your heavy sack tightening and your hard shaft throbbing as you feel yourself about to spill your seed. Your slime girl feels that as well, or perhaps senses it in the same way you sense her emotions, and she moves her hand up to the very tip of your member with a final upward stroke. As she does, her hand again takes on the shape of her regularly dainty appendage and she is quick to cup her palm over the swollen head of your manhood.

Just as the warm, wet hand touches you, encompassing the tip of your rod, your climax hits you and you arch up into her touch, moaning in pleasure as thick, hot semen spurts from the end of your erect staff. It spurts from you and directly into the slime girl's palm, the thick milky liquid seeping into her slimy flesh and being drawn into the core of her body through her arm. As she is made up of one large mass of slime, there is no need for her to ingest her chosen sustenance through her mouth. No, she can take it from anywhere upon her viscous body and she does just that with the voluminous load you empty into her hand.

You cum hard and long, her arm hazy and clouded with the amount of semen you spill into her as she draws it into the core of her body, down near her belly. She draws all of that seed she stroked from you into the center of her very being and, when it gets there, it seems to dissipate into her gooey mass as though being digested. By the time you have emptied yourself into her hand, falling back and panting with exertion in the afterglow of your first orgasm induced by somebody else, she has drawn all of your cum into her and digested it.

She smiles as the last of the cloudiness inside of her disappears into the green goo of her body, looking supremely satisfied as she puts a hand to her belly and rubs it as one would after eating a filling meal. That's exactly what you suppose she did though, isn't it? An odd thing to think that she has taken sustenance from your carnal pleasure, but it's not something you think upon for too long as you lay back in that pile of books, feeling completely spent.

Your slime girl looks at you, laying sprawled in those books, and she coos happily and affectionately as she climbs up onto you, curling up next to you as though seeking your warmth and company for a nap. Half of her warm, slimy body rests atop your own (most noticeably her thigh which rests upon your now softening member and seems to surround it with the pleasant tingling warmth of her gooey embrace) and she rests her head upon your chest as she makes soft contented noises. She looks up at you and her lips part into a pantomime of a yawn, the only sound leaving her a soft burble as he does, before she snuggles in close to you with her head on your chest once more and her arms wrapped about your midsection.

You think for a moment about how strange life had become from the moment you summoned the slime familiar that now rested at your side. You would have never expected to be laying in a pile of books, sexually spent and content, with a voluptuous goo girl next to you. No, you would not have expected that at all...but you couldn't say you minded it. Not one bit.

So it was with a sleepy sort of smile that you put an arm around the slime girl and placed your hand atop her head to pat her "hair" gently. "Lime. I'm going to call you Lime. That's your name now. All right?", you tell her and she glances up at you from her place resting on your chest to give you a warm smile, her emotions of joy and gratitude conveyed to you through the physical contact and magical bond you share.

"Laaaaa....eeeeee....Liiiiiii.....eeeeeeemmmmmm.", she breathes out softly, trying to copy the sounds you made that are her name. She doesn't quite manage it, but she seems to get close enough to please herself as she smiles happily and snuggles against you anew, apparently happy with the name you gave her.

And you, content with her happiness and with your current position curled up with your slime girl and feeling drained after your surprising experience with her, end up drifting off to sleep in the pile of books, your slime girl burbling happily beside you.