mutants and masterminds 3e – How can I do a “Fastball Special” to throw my ally at an enemy?

With the caveat that Green Ronin only counts the Hero’s Handbook as core rules, the Power Profiles: Strength Powers supplement suggests:

Lastly, a strong enough character can throw another character as a makeshift weapon! If the other character is a willing partner, this is a standard action for the thrower, who makes a ranged attack check to put the thrown character on-target. The thrown character gets to make either a charge or a slam attack using the throwing distance rank as speed rank (Deluxe Hero’s Handbook, page 246 and 250, respectively), and the thrown character’s initiative moves to directly after the thrower’s.