Their lovemaking is slow and thorough for once rather than desperate and rushed - they are finally getting used to one another.
Charles’ breathing is hitched and Erik knows he will begin making those adorable (hot) kitten mewing noises any second now; he grins at the thought and adjusts position to allow for the deep thrusting guaranteed to evoke said kitten noises.
Then Charles says, “I - ahh - most certainly - do not.”
Erik grins so wide it hurts, but he does not halt the proceedings. “You do not what, now?”
“Make sounds - ahhh - like a - a cat - when I-” he falters silent, either because what Erik is doing to him is supremely distracting, or because he is ever (so strangely) bashful when it comes to actually using words for any of the things they do to each other with their clothes off.
“I beg to differ, and I should know,” Erik says, all innocence. After a moment’s consideration he adds “Mrrow?” complete with alveolar trill - not even close to the actual sounds Charles makes, as Erik suspects complete accuracy would throw a wrench into the entire works.
“Don’t - ah - don’t do that,” Charles says. The reproach is palpable.
"Mrrow," Erik says again. "Mrrow, mrrow...mrrow?"
"Stop that!" Charles demands. His breathing is ragged now, and Erik can see the determination not to mew, squeal like a girl or make any other of the sounds that so fascinate Erik.
Erik attempts a solemn face and thinks (mrrow mrrow mrrow MRROW), pushing it in Charles' direction so he can't miss it. At the look Charles gives him he has to cease all other movement as he convulses in silent laughter against Charles' shoulder and tries to regain control.
"You are such an ASS," Charles says.
Erik laughs so hard he's tearing up, near choking on it, God, he can't remember the last time he laughed like this.
"Are you done?" Charles asks, testily.
"Mrrow!"
"Go to hell, get off me," Charles says, and Erik does.
Charles proceeds to pout very prettily - knowing exactly what that pout does to Erik, no doubt; he has never been able to abide pouting on any other being, but on Charles it falls under the heading sexyadorablehot.
Erik does not acknowledge this in any way, but rolls onto his back and lies there snickering and snorting to himself and venturing the occasional "mrrow" or (mrrow) in Charles' direction. Despite the protests from southerly parts of his body, he knows it's more than worth it.
"You may think your little joke is worth a case of blue balls, but there you would be wrong," Charles says snippily.
"If you would stop eavesdropping on what I think, we would be done by now," Erik points out. "I am unconcerned about it." Upon which he stretched out to his full advantage with both hands behind his head to give Charles the best possible view of everything, and begins to further broadcast one dirty thought after another in Charles' direction - interspersed, naturally, with the occasional (mrrow?).
"I could make you stop," Charles growls - actually growls! oh, excellent - and still doesn't manage to sound the least bit threatening.
"Yes, but you won't." Of this Erik is certain, at this one moment at least.
"Well no," Charles concedes. "But it remains that I could."
Erik sits up abruptly and booms "Wroof!" right into Charles' ear.
Charles falls off the bed in his surprise, and when he gets up his face is actually purple, and Erik is suddenly certain that they will each be sleeping in their own room tonight when Charles begins laughing, too. It's enough to set Erik off again, and it is a good few minutes before either of them is ready to go again.
When Charles finally comes, mewing and screeching and all despite himself, Erik breathes one final "mrrow" against his ear and is not the least bit shocked when Charles threatens to banish him from his room and his bed forever. This of course does not happen, and they make several more goes at it, during which Erik is very obvious about not saying or thinking it again despite how much he wants to.
"'M so sorry Charles," Erik says some time later, as his face begins to meld into his pillow.
"Oh you are not, you great bloody liar," Charles grumbles.
"'M too."
"Oh shut up, you."
Erik does.
It won't last, it can't last, and it doesn't; but even when the line between them first is drawn then blurs (over and over again), Erik Lehnsherr ever enjoys exasperating Charles Xavier.