The sacrament of Confirmation is accomplished by an anointing with a special blessed mixture of oil and perfume, known as sacred chrism. The words which accompany this anointing are “Be sealed with the gift of the Holy Spirit.”
When a person is thus signed with chrism, not only the skin but also the soul is marked. In fact, Christian tradition holds that (like Baptism) once the sacrament of Confirmation is validly received it is unrepeatable: In traditional terminology we say that these sacraments impart an indelible “character” (see pars. 1305-1305 of the Catechism of the Catholic Church).
Things which are done only once ought never be experienced in a hasty or irreverent manner. This is one of the main reasons favoring careful preparation for the important occasions of Baptism and Confirmation. (And marriage, and ordination, and so many other important spiritual steps!) The moment of such special grace ought to be savored, and understood to be as rich as possible. Have you ever tried making a short list of things you wish you’d appreciated more at the time? It can be fun, but also a tad depressing. At least we can resolve “from now on” to make every moment count!