double-tongue

from The American Heritage® Dictionary of the English Language, 5th Edition.

• intransitive verb To play a rapidly repeated series of notes on a wind instrument by placing the tongue alternately between the positions for t and k.

from The Century Dictionary.

• noun Duplicity; deceitfulness.
• In music, in playing the flute and certain brass instruments, like the cornet, to apply the tongue rapidly to the teeth and the hard palate alternately, so as to insure a brilliant execution of a staccato passage.
• noun A kind of dwarf butcher's-broom, Ruscus Hypoglossum, of southern Europe: so called from the appearance of the cladodes. See Ruscus.

from the GNU version of the Collaborative International Dictionary of English.

• noun Deceit; duplicity.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb play fast notes on a wind instrument