Remember, this can only be done in Versus (must be public), not Versus Challenger.
There are many easy friendships. To list some: Cyrax (run,run,run, up), Stryker (A,run,run,A), or kung lao (run,A,run,B) These can each be done from any position on the screen.
You must not block the entire 2nd or 3rd round in order for these to work.