A right hand flam followed by a right tap and a left tap, or (using a left hand lead) a left hand flam followed by a left tap and a right tap. It is often used in the place of a flam accent, since repeated flam accents will have three taps on the same hand in a row, where repeated swiss army triplets only involve two taps on the same hand.
Courtesy of DrumRudiments.com
Applied to drumset
Courtesy of FreeDrumLessons.com