Mpreg? Really? *cough* Perhaps I could entertain you with a little:
Severus stood in front of the mirror he had conjured, sliding his hand under the curve of his belly, delighted to see his cock still looked the same as he remembered it. He stroked it lovingly.
"Severus?" Harry's voice held a question as he stepped into their bedroom. "Are you all right?"
"Of course I'm all right!" Severus snapped in an obstreperous tone. "Can't a man enjoy a wank?"
"Of course," Harry soothed as he sank to his knees, "but allow me to take care of this for you."
Severus sighed as his husband's skillful hands stroked him to hardness and talented mouth slid over the tip of his length. As that wicked tongue went to work, Severus conveniently forgot it was the skill of the brat's mouth that seduced him into letting down his guard and put him in his current state.
A glance in the mirror showed his lover on his knees, a look of bliss on his handsome face as Harry bobbed his head, one hand pressed against Severus' swollen belly. Sliding one hand into the tousled hair, Severus covered Harry's hand, resting over the unborn child they had created. The combination of sensations overwhelmed him and Severus' climax stole his breath as his Harry had stolen him heart.