Yes, slowly...

He stops sucking and looks up at you pleadingly. "Uhm, Sir?"

"Yes?"
"Could you, uhm, put your penis in my..."
"You want me to fuck you ass?"

He blushes again and shudders in anticipation. "More than anything."

You lead him into your bedroom and push him down on your bed. Despite having just sucked your cock, he still clings to the last shreds of his shyness. You flip him onto his back and Place his legs over you shoulders. The tip of your dick is just touching his quivering asshole. Then you stop.

"What is it Sir?"
"Beg for it."
"What?!"
"I said beg for it or you´re not getting any. Beg for it like a dirty little whore and I´ll fuck you like you´ve never been fucked before..."

He bites his lower lip in that o so sexy way. Then he takes a deep breath and begs. "Please sir fill my slutty Little hole with your huge divine dick! Please fuck me til´ I pass out and make me cum like a volcano.!"

Wow, quite a lot of lust in him. Satisfied, you guide your dick into his tight ass. At first its tight, but it gets even tighter as you press in. His ass hugs every millimeter of your dick, making you raging hard if your weren´t before.
After a while your hips meet and he exhales. Then you slowly pull out until just the tip is left inside...