When they first start having sex, there are times when Flynn adamantly insists on keeping his clothes on, and Yuri, by common decency, always bites back any smart remarks and does the same. Yuri doesn't like it feel. The rub of fabric on his cock is incomparable to Flynn's mouth or his ass, and Flynn, for being the one who insists on it in the first place, doesn't ever seem too pleased either. Yuri grinds his knee against Flynn's crotch, trailing kisses and bites down his neck and chest, letting Flynn's moans guide his path, until he is pushed back up again. Flynn rubs at the bulge in Yuri's pants, the friction enough to get the black haired man off eventually, but it is oh so much less intimate than really having sex. But if it's for Flynn, Yuri is willing to deal with it.
It is always after Flynn is injured. Yuri's best guess is that Flynn, bloody bandages covering various parts of his body, is afraid to hurt himself worse. Clothes provide an invaluable protection when injured, and when a sword has just sliced through your leg, all the protection you can afford is the best.
When he finally asks why Flynn does this though, Yuri receives a vastly different answer than the one he had been expecting.
"I don't like how you look when you see my injuries."
Yuri smirks and lifts an eyebrow. "And how do I look exactly?"
"You look sad. You look like you think it's your fault I'm hurt." Flynn's voice is sheepish when he answers, as if he's embarrassed to reveal his true reasons for wanting to stay clothed.
Yuri is taken back for a moment, and when he recovers, he can't help but soften his smirk to a simple smile. "Half the time it is my fault. But…" He cocks his head, considering. "It's your fault, really, for not blocking my blade. And when it isn't my sword that cuts you, why should I feel guilty about you getting hurt?" He leans forward and kisses Flynn's forehead lightly, and the blonde rolls his eyes.
Yuri may be a good liar, but to Flynn, he's transparent.