Throw A Fully Charged Ally And Have Them Get 100 Cumulative Kills.
Step 1: A Teammate "Balls Up"
Step 2: Grab Them
Step 3: Hold The Throw Button Down Until You Put Them Over Your Head
Step 4: Release
Hardest Part About This: You Have To Rely On The Person You Throw Having Good Aim.
Good Luck!