John Sheppard bit his lip to keep from snickering aloud and waking up his victim. Carefully he swirled shaving cream into the sleeper's outstretched hand (the other being tucked behind his head). When that went off without a hitch, Sheppard felt more comfortable and leaned over to place the shaving cream can on the table.
His victim twitched and mumbled something involving jello and pie. Or maybe pi. John couldn't be sure. He held his breath until the sleeper subsided. Thankfully his shaving-cream-filled hand was still intact. John let out his breath and took another before proceeding with his evil plan. He reached over and tickled the other man's nose. He snuffled, but didn't move. John rolled his eyes and tried harder, feathering light touches over his nose where he knew it would be most ticklish.
Rodney McKay's hand came up and shoved Sheppard right in the face, knocking him back off the ottoman and onto the floor. "Would you let me sleep for just one more second," Rodney groused as he sat up groggily. "I was in the lab with Radek all night and you wouldn't think dealing with his stupid ideas would be tiring, but it is. Incredibly ti-"
That's when he noticed Sheppard picking himself up off the floor dazedly. He stared in confusion at the shaving cream covering the colonel's face. "What are you-" Then he looked down at his own hand and found the remnants of the prank. McKay smiled smugly as he put the pieces together and looked back up at Sheppard. "Gotcha."
"That didn't go quite like I planned," Sheppard admitted sheepishly, wiping cream out of his eyes. Rodney burst out laughing and John couldn't help but smile at him. "Happy April Fool's Day, McKay."