She can hear someone knocking, but she doesn't have the breath or the inclination to answer -- she only hopes Christina locked the door when she followed her into the bathroom, or whoever it is will see more of Summer than either of them probably want. She's trapped between Christina, who is pressed against her back holding her in place with a hand on her breast and the other rubbing her clit through her panties, and the cool porcelain of the sink, skirt pushed up around her hips, teetering on the edge of coming, like she has been for what seems like hours.
Christina pulls her mouth from the tender skin at the back of Summer's neck long enough to holler, "I'll be out in a minute," before she licks a stripe along the side of Summer's neck, punctuating it with a nip to the earlobe. She flicks her fingers over Summer's nipple as she finally, finally pushes aside her panties and sinks two fingers into Summer's cunt. It's so good Summer almost cries out, but at the last second, she remembers Christina's "Shh," when they started, so she bites her lip to stifle the sound.
Christina sees, is watching Summer's face in the mirror, and she smiles against Summer's neck as she pinches her nipple in time with the thrust of her fingers. Summer smiles back, and pushes against each thrust, wet and slick, wanting more, and when Christina asks if she can take another finger, she nods and pushes against Christina's hand. She's never been this close for so long; she feels stretched and full and yet she wants more, needs more.
Christina is fucking her with three fingers now, biting and sucking the back of her neck, rolling her nipples between thumb and forefinger, and it's so good, but it's not enough. Summer fumbles past the hem of her skirt, past the edges of her soaked panties to where Christina's fingers are pushed deep, swiping at the wetness there, slicking her fingers before she starts to circle against her own clit, working it in the same rhythm. It's a matter of seconds before she's coming, arching into Christina's hands and mouth, biting her tongue to keep from screaming when Christina keeps fingering her, pushing her towards another orgasm.
Christina slides her hand from Summer's breast to her chin, turning her face for a kiss. Summer presses in hard, licking against Christina's lips, her teeth, her tongue, sealing their mouths together, using the kiss to muffle her moan as she comes again.
Her cunt is still tight and twitching when Christina slips her fingers out, trailing them down the inside of Summer's thigh. It tickles, and Summer tries to turn, to move her thigh away from the wet slide of Christina's nails, but Christina pushes her forward, over the sink, and tells her to "Relax," and to "Stay."
Summer isn't sure what to think about that, but before she can decide whether or not to move, Christina has knelt behind her, and is pulling her panties down, encouraging her to step out of them, and tossing them aside. Then Christina is back, smoothing her hands up Summer's thighs to where they meet with her ass, pushing Summer's legs apart, spreading her open and sliding her tongue along the slick folds of skin that surround her clit, humming against her as she licks and sucks, and just like that Summer is on the edge again.
She braces her arms against the sink and pushes into Christina's mouth, arching her back to give her better access. Christina sucks Summer's clit between her lips, flicking it with her tongue, at the same time as she pushes her fingers back inside, and the sensation is almost too much. A few more twitches of tongue and fingers are all it takes for her to come again; this time she does moan, the echo of it loud against the tiled surfaces of the bathroom.
When Christina pulls away, Summer isn't sure her legs will hold her up, and she's absurdly glad for the support of the sink. When they hear the knock at the door, she realizes it's been a lot longer than a minute since the last time someone knocked, and she starts to giggle as she decides she doesn't really care.
Christina hollers that they'll be out in a minute, and kisses the back of Summer's thigh one last time, before she's pulling her up, pushing her skirt down, brushing her tangled hair off her face, kissing her softly and telling her how beautiful she is. Summer is blissed out, happy and sated, and she watches in the mirror, content to let Christina put them to rights before they rejoin the party....