little brother who brings his big brother with him everywhere for scary dog privilege. little brother who has to hold his big brother back to keep him from snapping at anyone who gets too close. little brother who insists "he's really sweet actually, he just has to get used to your scent" and fails to realize that he's the only person big brother is “really sweet” with.
big brother who sits on the floor at the foot of little brother's bed and watches the door to make sure no one comes into his room while he sleeps. big brother who becomes increasingly obsessed with all the sounds and smells his little brother makes when he pleasures himself every night. big brother who wants nothing more than to be the one drawing those sounds out of him. big brother who never looks away from the door (because a guard dog doesn’t leave his post) but trembles with the effort of keeping still.
little brother who finally takes pity on him one night and pats the mattress to invite him up. big brother who scrambles onto the bed eagerly and starts humping his leg, covering his face and neck in slobbery kisses and play bites. little brother who laughs and shoves his face away, then warns him to "be gentle" before spreading his legs.
big brother who has to try so hard not to let his excitement get the best of him as he finally mounts his little brother after weeks of restraint. big brother who is too enthusiastic and clumsy to really treat him delicately, but who never stops trying to be a good dog. big brother who can't help getting faster and rougher every time his little brother calls him a good boy or thanks him for protecting him.