Found in Brock Baker's parody of Rebecca Black's viral song, "Friday". It is used to describe the wavy motion of one of the kid's hands when they're driving in the car.
Person 1: *waves hand* "MY HAND IS A DOLPHIN!!!!11ONEONE"
This syndrome has been made popular by Rebeecca Black's "Friday" song.
The syndrome has been relatively ignored until this point. This has been a condition that effects all ages and races. Some of the signs of My-hand-is-a-Dolphin Syndrome (a.k.a. MHISADS) is the need to roll down the window in the car when you are "kicking it" in the front-seat or in the back-seat with your friends, then sliding your arm out and moving your hand and forearm up and down in a fashion which appears like a dolphin riding a bow of a ship.
Ryan - "Yeah, i was taking Nick home and all of a sudden, he started moving his hand up and down out the window like a damn dolphin"
Kevin - "Wow! I guess he caught that My-hand-is-a-Dolphin Syndrome. That's crazy! Hope you don't get it"
The ability girls and women have developed to hold several items at once in one hand. The skill has been developed due to the lack of pockets in women's clothing.
I thought she'd need multiple trips to carry her phone, keys, wallet, and Starbucks to her car since she needed the other hand to open the door, but she used her impressive girl grip to carry everything in one hand.