READ IF YOU DONT'T WANT TO DESTROY YOUR MMR IN PLACEMENT MATCHES.

A diamond player told me that duoing with someone during my placement matches wrecks my mmr. HOWEVER, i can duo with someone AFTER my pacement matches and it wont wreck my mmr, as long as we are in same duo range. Is that true? So i cannot duo until im done my placement matches just to be safe??

Please respond if you are sure what the answer is. Thx.