a chisholm is a person who gets overly excited when other people are re-telling life stories
when said person is about to do a "chisholm" he will get a look in his eyes of pure excitedness
man 1 "so this one time i remember saving the queens life in the middle of the afghan desert"
man 2 "oh god here he goes again he is doin a "chisholm" again"
man 3 "for fuck sake not again last week he was in the s.a.s"