“A” stands for

“No, it’s OK. Go ahead.”
I had no real idea of what go ahead was actually supposed to entail, but my pelvis did seem to know perfectly well. I started rocking back and forth, slowly and gingerly. My cock moved in and out of his asshole, a feeling so warm and tight it felt unlike anything we’d experienced together so far.
“Oh my you are fucking me!”
It was like he needed to say that out loud before it could register with me. The realization hit me like a hammer.
“I am…I am fucking you!”

And then I really fucked him. I held on to his bent knees and started pumping in and out with long strokes. Careful at first, but I took the delight on his face instead of another flinch as an encouragement, and gave up all reticence. I fucked him hard now, deep and fast pumps in that tight hole of his. His cock bounced on his belly with every stroke. I grabbed it in one hand and stroked it the same rhythm as my shoves, faster and harder with every passing minute. Not many minutes would pass though. I felt an intense heat building up in my groin and intensified my strains, diving in and out, concentrating on the squeeze that passionately massaged my cock to an unprecedented climax.