Don Draper walked into his office, and stopped as he saw a small but burly figure sitting behind his desk. Intrigued, Don threw his hat on the stand, and then closed the door.
"Hello.... Dick Whitman" rasped that familiar voice.
"Excuse me, do I know you?"
"You did."
Don got that face that he gets when something profound hits him, or he remembers something about his past. Maybe he would cry, maybe not. Instead, he did was he always did - he went over to the bar and poured two stiff drinks. He handed one to Varric, careful not to touch his leathery fingers.
Varric took the scotch and swirled it in the glass, ever so gently. He almost didn't see it. Don's flaming katana coming down upon his head. But Varric moved just in time, the scoth never finding harm.
"There can be only one, you know" Draper recited.
Varric was ready, though. He gave a mighty man-yell and hurled himself at Donald/Dick. Soon, the two were crashing through four buildings at the speed of light.
That is how, in his 36 years of seducing women, Don Draper went gay.