i just know for a fact that charles has a tragic, chronic giggler disease in bed. like, yes of course, crying during sex beautiful and true, but have we ever considered him smiling so widely that they literally cannot proceed with anything, because edwin keeps asking him "what made you laugh this time? what is so hilarious?", and charles needs to duck his head because how can he explain that he's incandescently happy and it's not going away. "sorry we can't kiss, i can't control my joy long enough to relax my mouth. oops." and he's like "okay, okay, i got this, for reals this time"; it takes edwin palming both of his cheeks to pull charles in and charles just. grins. again. teeth clinking in the middle. he would be mortified if this was anyone else or if edwin decided that's enough and maybe we should play cluedo instead.
he's doing neither, because edwin's a good person like that. he finds a way to tickle him along the sides so that charles has a reason to have a chuckling fit at least.
and it must have been a complete shock to edwin too. if he dared to imagine it at all, he never would've guessed intimate relations could be so... freeing. that you can laugh yourself to tears and still keep going, that your lover can have such a wonderful time exploring everything unknown about you that he's glowing inside and out. from what he's gathered, sex is supposed to bring a certain level of seriousness and it's like, the exact opposite with charles— frankly, it's just more of charles, everything about him distilled and intensified, his normally warming smiles are blinding now, the way his limbs move thrice as graceful as when he's on a case. you know edwin has a list of favourite charles sounds, and somewhere near the top lands the breathy, unabashedly happy huff which morphs into a quiet moan by the end. he loves it. he'd be lacking without it. edwin is the luckiest ghost on earth, it seems.