- - Please visit: Legacy Horn Experience - -
Scott Whitener in A Complete Guide to Brass notes that
The so-called tongued release does have its place…. Professional players often make use of it by adding a “t” at the end of the note (“tut”) in very staccato passages. This produces a shortness and crispness that can be obtained no other way.
A mantra heard over and over in traditional brass teaching is to never cut off notes with the tongue. It sounds right, and is true in a general sense, especially for lyric playing. It is however actually pretty well known in some horn circles at least that “tut-tut-tut” is considered correct in exactly the circumstances as outlined above by Whitener, to produce a short and crisp staccato.
Bruce has a longer article here. 
This is a topic that comes up pretty often with students. Many if not most brass teachers say not to cut off notes with the tongue in any circumstance, echoing thoughts expressed as fact by Farkas, but I feel very secure in saying that this idea is clearly mistaken. And I can point to still older sources and other schools of horn teaching for backup.
In the end, think it through logically: without the tongue being involved how in the world else is a crisp staccato produced? Something stops the note short or it would trail naturally off into a soft, fluffy ending.
The big picture problem here is that teachers say to never do it then students following their instructions try to play staccato and fail. The problem is they can never figure out how to play staccato as they are fighting nature. Of course the end of the note is cut off in some circumstances; there is a place for it.
That all being said, I suspect that many fine brass colleagues I have had would still say to never ever cut off notes with the tongue or you will die. Maybe not the death part but you have the drift of what they say and believe to be a great truth of brass playing. But clearly in horn we make use of this articulation a lot in producing staccato, even if it is something we are perhaps only vaguely aware of or perhaps think we are not doing.
Listen to Dennis Brain play a Mozart rondo, and make it sound like that. Done lightly or in a more heavy manner, tut-tut-tut really is the answer sometimes and especially so on a slow responding instrument such as the horn.
