Take "liturgical dancing." (Please!) In its proper use, this phrase means refers to "dancing that takes place in the liturgy in those cultures for which dance is an integral form of worship." In its twisted and misappropriated sense, often invoked by Western folk today, it means "children hopping about with streamers because isn't that cute," or occasionally "stealing someone else's proper form of cultural expression and shoe-horning it in where it doesn't fit, like a Ming vase in a log cabin."
Or consider the "spirit of Vatican II," which ought to mean "the intentions, principles, and presuppositions that inform and animate the texts of the Council," but which is usually used to mean "an attitude of revolution and rupture having little to no reference to the actual content of the Council."
So, too, with "pastoral application." This phrase, when found in canon law or the teaching documents of the Church (or when it's like appears), refers to the application of the abstract truths of the faith or the general laws of the Church to the concrete situations of the faithful with the good of the faithful in mind. It's much more readily understood how this term applies to canon law, as the entire notion of law centers on the application of generic formulations to particular incidents or situations (e.g. does this or that event match the definition of murder, or fraud, or jaywalking). And the law consists much more of disciplines than doctrines, of prudential choices for good order rather than eternal and immutable truths, which is why the law is filled with exceptions "for a just reason, for a grave reason, according to the judgment of the local ordinary," etc. The pastoral application of the law consists in applying these laws and their exceptions (where the law allows) for the benefit of the flock of Christ. If St. Patrick's Day falls on a Friday in Lent, and your diocese has St. Patrick as a patron, it's proper for your diocese to celebrate its patron with due joy and solemnity, and thus just for your bishop to grant an indult from the obligation to abstain from eating meet that Friday. It's for the good of the people, and it's within the bishop's competence to do so.
But when people talk about a "pastoral application" of the Church's teachings on matters of faith and morals (usually morals), what can that mean? Do these truths sometimes not apply--are they occasionally not true? Or can any ecclesial authority grant an exception to the moral law? "In honor of St. Augustine, I'm granting an indult on stealing--but only stealing pears!" Of course not. That's absurd.
And yet when the topic of certain sinful acts arises--say, divorce, or contraception, or homosexual acts (why is it always about sex?)--some people get pained looks on their faces and close their eyes and ask in that whispery, NPR interviewer-type tone, "But how can we approach this pastorally?"
Now, I'm all for a pastoral approach, if by "pastoral" we mean "with the good of the faithful in mind." I would advocate for a kind and charitable discussion in which we assure them of our love for them and our concern for their well-being, and listen to their thoughts and about their experiences, and acknowledge the difficulties that they face, and explain how those actions are not in accord with how God made us to act and with what will bring us true happiness, and encourage them to not despair or give up.
But too often, what happens under the auspices of "pastoral care" is a granting of license to sin. "Oh, it's OK, life is messy, you have to do what's best for you, follow your heart, God just wants you to be happy, we don't want to upset you, please don't get mad at me, can we still be Facebook friends" usually followed by "the Church is behind the times, it'll come around eventually." To quote Kaiser Soyze: "And just like that *poof*: he's gone!" Here comes the magic word "pastoral," and the truth has disappeared. This "pastoral" approach sets truth on a shelf, like a decorative plate that one looks at and admires but which of course is entirely impractical and would never work for use in real life.
It is not a pastoral approach to tell people it's OK to do what the Church knows to be wrong and to be harmful for people. In doing that you give people permission to live outside the truth and put their souls in jeopardy of being sundered from God forever. This is looking out for the good of others? This is shepherding the sheep?
This false use of "pastoral" is not an application of the truth, but a dismissal of it. Truth is left at home while the kids head out to a party at their friend's when the parents aren't home and they found the key to the liquor cabinet. You might think truth is getting in the way of you living your life, but really truth is just trying to stop you from ending up with a hangover and a missing wallet.