England prop Joe Marler has been given a formal warning for posting an obscene tweet about former Australia coach Bob Dwyer.
The Rugby Football Union said Marler - who immediately deleted the remark - was "extremely apologetic".
Dwyer had claimed England were scrummaged illegally during the win over the Wallabies on Saturday.
Marler asked to miss the tour to Australia to "recharge his batteries" after a difficult season.
In April, the Harlequins prop was fined £20,000 and given a two-week ban for calling Wales prop Samson Lee "Gypsy boy" during the Six Nations.
He was suspended for a further two weeks for kicking Grenoble hooker Arnaud Heguy in his first game back.
The RFU said the warning would remain on Marler's disciplinary record for five years and could be used in any future proceedings.
Eddie Jones' side will seal England's first series win in Australia if they win the second Test in Melbourne on Saturday.