Chapter Text
The first time it happened with Sherlock, John, with a certain amount of smug satisfaction, thought that the plant had gone into shock. It had stayed completely still while Sherlock, both encouraged and hindered by John never really letting him out of a second kiss, struggled out of his clothes. And John was suddenly reminded of how much work sex actually was: the plant had spoiled him in that respect, all he had to do was let it have its way with him, and now he had to help Sherlock out of his shirt, his trousers, his pants, coax him onto the bed, and maneuver with and around him, because though they both agreed that they deeply and urgently needed to shag each other senseless, all they were managing to do was grab and push and get in each other's way.
Eventually, after such communication as was possible between kisses and grunts and stuttered moans, Sherlock let John prepare him, and it felt like an excruciatingly slow business. John swore steadily as he worked his fingers, slicked with the nectar still glistening on the plant's equivalent of leaves, into his flatmate's arse. And he continued to swear, though for vastly more satisfying reasons, as he began to fuck Sherlock, slowly at first, because he was still trying to be considerate, and then harder as Sherlock egged him on with groans and touches and the way his body simply took John in. John still had enough of his mind left to wonder if the plant juice had anything to do with that, but he didn't pursue the idea because Sherlock came, long fingers curled around his prick as John fucked his arse, and John could feel every shred of his orgasm where they were connected, and it didn't take much longer for him to finish after that.
That was when the plant finally caught on. In the predawn light, through the woolly-headed realization that he had just shagged Sherlock Holmes, John saw the root-tentacles stir, lengthen, and snake their way to Sherlock's lush arse. The consulting detective made a half-hearted sort of whimper as other appendages turned him on his side, and he gasped when three of the root-tentacles - they were thinner than the others, and the tips branched into spindly fibers - pushed into his arse at once.
"Weird, isn't it?" John propped himself up onto his elbow to watch, let Sherlock take his other hand and squeeze it while the tentacles worked. A few others had curled around his own cock, but John was far too used to that by now.
"Weird isn't even where it starts," hissed Sherlock. "You've never had these ones in your arse, have you? Since it's your semen they're after?"
"I've had a lot more than that in my arse," said John, a touch of rebuke in his voice (who started this plant business in the first place?). And he relented because Sherlock was writhing so enticingly, even with a fat tentacle wrapped around his waist to keep him still. He opened his arms. "Oh, come here," he murmured, and he held Sherlock to his chest while the plant finished with him.
It was interesting to note that while the plant went after every drop of John's ejaculate - to the point that it dipped a little tendril into his glans, making him shudder - it left Sherlock's well enough alone.
Morning was breaking over London by the time it was done, and the two of them slept till noon.