A discrete and gentile vibration, given to a significant other, in order to show affection. The significant other is often referred to as a "ploob". Thus, a "ploob shake". This can often occur with a hug, and as a reminder of love during a stressful time.
"Ploob, I need a ploob shake in order to feel better."
by Loving Ploob vc February 01, 2007