The size actually matter
Rather than a story I can only call this a scene.
I hate being so slow to write.
Edited.
"Well, you have the size I imagined," a red fox told to his partner while gently hitting his own chest with a riding crop. "I guess it can't be helped." He was athletic and of average height; his only clothes were black leather hip pants.
His interlocutor, a stockily built bernese mountain dog answered, "I know it's not a big thing, but 'it's not about the size of the boat but the motion of the ocean that matters'. Right?" Certainly the size of his penis was nothing impressive, even rock hard it barely surpassed the four inch mark. He was completely naked, his wrists and ankles were attached to a St. Andrew's cross. Said position left his kiwi-sized testicles hanging exposed between his muscular legs.
"Don't be self-conscious about it, I really like it." The fox approached the taller canid. "To being honest, I have a thing for big fellows with small penises," he said as he placed his arms around the dog's neck, making their muzzles almost touch, and pressed his lower body against the dog's, enclosing the latter's erection between the fox's cream furred abdomen and his own fluffy front.
The bernese dog moved his hips forward, seeking more stimulation. "Really? Why?" After asking that question his expression changed in an instant from delight to absolute pain when he felt a swift knee flattening his puppy makers against his pelvis. His eyelids opened completely as his honey-colored eyes trembled violently, his jaw dropped, and his diaphragm let out a high pitched shriek. He would have collapsed to the floor if not for being tied to the cross.
"Small mushrooms don't get in the way."
The fox withdrew his kneecap from the dog's aching gonads, but far from a relief, letting his balls fall back into their sack reasserted the initial pain. Trying to hold back the tears, the bigger canid could only could shut his eyelids tight and follow his reflexes; he attempted to close his legs while moving his hips rearward in a futile attempt to protect his defenseless testicles.
The dog reopened his now crossed eyes while shivering wildly just as an unerring kick crushed his balls against his pelvis for the second time. A piercing howl exploded from insides of the tortured canid. That was a blow the bernese dog wasn't expecting. Likewise, the fox didn't expect the dog to cough his safeword so quickly.