"Deception, Conception 2"
The heat didn't kick in until partway through tea, when Moriarty began to slaughter an apple with confident hacks, appealing to Sherlock's darker side; the show of dominance from the Alpha made Sherlock's heat hit full force.
He would never be sure who moved first; but Sherlock launched himself out of his seat around the same time that Moriarty reached forward to grab him, resulting in Sherlock straddling his enemy's lap and tearing at trouser fastenings.
"Prove that I saved myself for the right Alpha," Sherlock said, panting as a finger thrust into him, "the one Alpha who could hope to achieve outwitting me, who would ensure progeny of a high intel— ah!" until he was cut off as Moriarty deflowered him with one powerful downwards yank.
The obvious sequel to 'Deception, Conception'. Will possibly write another instalment, also three sentences long. Because I enjoy being a tease. ;)