So I have all of these published on my tumblr, but I figured I might as well keep back-ups over here. So... here you go.
"Sirius, I'm pregnant."
His face assumed a horrified expression. "I'm not the father, am I?"
Lily actually beat him around the head with a pillow. "No, you prat."
"Then why are you telling me?" He massaged his chest. "I swear my heart seized up…"
"How do I tell James?" she almost wailed.
"Well, seeing as I've never been pregnant with James' spawn," he said dryly, "I'm not quite sure. How about you just say it to his face?"
"Do I just walk up to him and say 'Hello, I'm pregnant?'"
"You are his wife, and knowing James, you two have probably been going at it like rabbits - "
"Shut up. Git."
" - so this should be expected."
She glared. "You're no help."
He stood up, grinning lazily as he reached for a pot on the fireplace mantel. "I know."
"What are you doing?"
"Incendio."
"Sirius, don't - "
He tossed in some green powder and said James' name. Too late, she started across the room.
"Lily's pregnant, mate."
"Sirius!"
"Good Lord, Potter, are you actually speechless? I'm bloody amazing - look at that, no words at all. Someone write this down; it should be inscribed into history books."