True, not Fabricated Communion
In sum, just as Calvin answers the Lutheran charge that his formulation reduces the Supper to a fallacious exhibition by emphasizing that the grace of the Supper lies in a true, not fabricated, participation or communication, so Calvin responds to the charge of a legal fiction by affirming the reality of the righteousness belonging to believers by virtue of their union with the righteous Christ. It is a true union, moreover, not with the grace or virtue of Christ's presence but with Christ himself, Christ in his flesh and blood, who is made present by the Spirit through faith.
Mark Garcia, Life in Christ: Union with Christ and Twofold Grace in Calvin's Theology (Eugene, OR: Wipf and Stock Publishers, 2008), 170