It occurred to the Eighth Doctor that Geronimo would have been puzzled to know he would be remembered mainly by people who were about to fall from a great height. (PROSE: The Shadows of Avalon) The Eighth Doctor joked to Charlotte Pollard that Geronimo taught him the greeting "How". (AUDIO: Storm Warning)
It seems his exclaimed name was employed as a battle cry.
The Doctor would occasionally talk about him as a lead in to shout "Geronimo!" (AUDIO: White Ghosts, PROSE: The Hopes and Fears of All the Years, COMIC: The Golden Ones) He also used the expression alone on occasion. (AUDIO: Dead London)
The Eleventh Doctor used the expression following regeneration when his TARDIS was plummeting to Earth. (TV: The End of Time) He frequently used the expression. (TV: The Eleventh Hour, The Beast Below, etc.)