Yuri isn't a fan of doggy style. It's not the pose he minds, oh no. It's the name. It makes him think of dogs. Namely, it makes him think of Repede. And that brings to mind all sorts of unfortunate mental images that he would really rather not have.
When he first mentions to Flynn that the name of the pose makes him uncomfortable, Flynn laughs before getting a strange, slightly horrified look on his face, and Yuri can't help but grin as he realizes Flynn is imagining the same thing he does when he hears the name.
It takes awhile before they're willing to attempt it again.
Once they do, it still takes some time before it's anything but uncomfortable.
Not the sex, of course. The sex is fine, great even. Yuri is able to wrap his arms around Flynn's waist even when he enters, fingers running up and down the blonde's cock. It's better for him, when he can move more freely, and Flynn is loser than ever. Ignoring the burn of the coarse sheets on his knees, Yuri's hips move in a rapid rhythm, and he leans forward along Flynn's back, brushing the blonde hair off his neck and kissing his shoulders.
Flynn, however, manages to hurt himself. In his attempt to turn his head so that he can kiss Yuri's lips, he twists his neck too far and his hand slips from the edge of the bed, sending him tumbling to the floor and leaving Yuri sprawled out along the sheets with a very confused, not to mention annoyed, expression.
Five minutes later, Yuri is lying on his back in the bed with his arm over Flynn's shoulders, and the knight is holding an ice pack to the swollen bruise on his forehead, all thoughts of actually finishing sex forgotten.
Yuri thinks he'd rather stick to frontal facing poses for now, and Flynn agrees.