sneaky peak
to creep up behind someone and watch them in silence without them knowing. A common practice in the cubicle work environment, and easily acheived when someone is working too hard.
"Dave was so engrossed in his work that Craig and I easily sneaky peaked him. We were there for like 10 minutes."
"The last time Dave sneaky peaked me, i started to smell a fould odor. I knew it was him!"
"The last time Dave sneaky peaked me, i started to smell a fould odor. I knew it was him!"