Tongue pulling treatment is most commonly attributed to Sir William Osler (1849-1919). However, origins of tongue pulling can be found in much earlier French references including Jean Laborde (1830-1903), Jean Viaud (1862-1946), and Raphaël Lépine (1840-1919).
It is hypothesized to work by stimulating the vagus nerve thereby easing the diaphragmatic spasms.
Treatment of singultus by traction on the tongue: an eponym revised. J Hist Neurosci. 2013;22(2):183-90. doi: 10.1080/0964704X.2012.728389.
[Stimulation of the root of the tongue can cure hiccup. 20 years of "unscientific" experience supports the thesis]. Lakartidningen. 1998 Oct 7;95(41):4477-9.