Can you use Yasuo Unforgiving on an ally unit?

Yes, you can use Yasuo, Unforgiven's ability on a teammate's unit in a 2v2 match.

According to RiftJudge FAQ #371, "friendly" includes your teammate, meaning Yasuo can move a teammate's unit. However, there are important restrictions regarding how this works in 2v2:

• Moving to Base: When moving a teammate's unit to a base, it must go to the unit owner's base, not your own base (RiftJudge FAQ #371).
• Restriction: While you can target your partner's units with the ability to move them, you cannot move your partner's units "to and from your base" (RiftJudge FAQ #5355).

In summary, you can use the ability to move your teammate's units, provided you adhere to the specific zone restrictions for 2v2 games.