Front rower Cherif Traore wrote on Instagram that he received the unwanted present, inside a rubbish bag, during a Christmas dinner for Benetton Treviso players.
"Apart from finding it an offensive gesture, what hurt me the most was to see that most of my team mates who were present were laughing. As if it was all normal," he said.
"I haven't slept all night," the 28-year-old added.
Traore was born in Guinea but has lived in Italy since the age of 7.
He plays as a prop for the northern Treviso club and for the Italian national Rugby Union team.