The priest is a human being who offers in place of Christ (the Orthodox say as an icon or image of Christ), but he also partakes, because he is no Christ and because he needs Christ just like the rest (and some would say even more than the rest!). Jesus did not need communion. The priest does.
Doubletalk!
CCC
1566 "It is in the Eucharistic cult or in the Eucharistic assembly of the faithful (synaxis) that they exercise in a supreme degree their sacred office; there, acting in the person of Christ and proclaiming his mystery, they unite the votive offerings of the faithful to the sacrifice of Christ their head, and in the sacrifice of the Mass they make present again and apply, until the coming of the Lord, the unique sacrifice of the New Testament, that namely of Christ offering himself once for all a spotless victim to the Father." From this unique sacrifice their whole priestly ministry draws its strength.
The Priest acts "...in the person of Christ". The Priest drinks the wind----Jesus drinks the wine. Simple!