Administration of the consecrated bread and wine of the eucharist at the same time, typically by dipping the bread in the wine and placing the moistened host in the mouth. Depending on local practice, this may be done by the communicant or the one who administers the wine. Historically, intinction has also been done by dropping the bread into the wine and administering the moistened host with a spoon. The term is from the Latin for "dip in." The BCP directs that opportunity always be given to every communicant to receive the consecrated bread and wine separately. However, the eucharist may be received in both kinds simultaneously, in a manner approved by the bishop (pp. 407-408). Some communicants prefer intinction because of concerns about contagious diseases or alcohol consumption. Separate intinction cups are to be avoided because they contradict the symbolism of the common cup.
Intinction was practiced in the east and west by the seventh century. The practice was also motivated by concern that the sacrament might be carried away for superstitious use. Intinction was opposed by the Council of Braga in Spain in the seventh century, and by Pope Paschal II in the twelfth century because it differed from Christ's action at the Last Supper. Intinction has been historically associated with giving communion to the sick.
[via The Episcopal Church]